The Bin/Amphiphysin/Rvs (BAR) domain, a dimerization module that binds membranes and detects membrane curvature; BAR domains are dimerization, lipid binding and curvature sensing modules found in many different proteins with diverse functions including organelle biogenesis, membrane trafficking or remodeling, and cell division and migration. Mutations in BAR containing proteins have been linked to diseases and their inactivation in cells leads to altered membrane dynamics. A BAR domain with an additional N-terminal amphipathic helix (an N-BAR) can drive membrane curvature. These N-BAR domains are found in amphiphysins and endophilins, among others. BAR domains are also frequently found alongside domains that determine lipid specificity, such as the Pleckstrin Homology (PH) and Phox Homology (PX) domains which are present in beta centaurins (ACAPs and ASAPs) and sorting nexins, respectively. A FES-CIP4 Homology (FCH) domain together with a coiled coil region is called the F-BAR domain and is present in Pombe/Cdc15 homology (PCH) family proteins, which include Fes/Fes tyrosine kinases, PACSIN or syndapin, CIP4-like proteins, and srGAPs, among others. The Inverse (I)-BAR or IRSp53/MIM homology Domain (IMD) is found in multi-domain proteins, such as IRSp53 and MIM, that act as scaffolding proteins and transducers of a variety of signaling pathways that link membrane dynamics and the underlying actin cytoskeleton. BAR domains form dimers that bind to membranes, induce membrane bending and curvature, and may also be involved in protein-protein interactions. The I-BAR domain induces membrane protrusions in the opposite direction compared to classical BAR and F-BAR domains, which produce membrane invaginations. BAR domains that also serve as protein interaction domains include those of arfaptin and OPHN1-like proteins, among others, which bind to Rac and Rho GAP domains, respectively.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662   4 SLRASFDSLKQQMENVGSSHIQLALTLREELRSLEEFRERQKEQRKKgmavprqsdcmevkspsweYEAVMDRVQKSKLS 83
Cdd:cd07671   57 TLKASFDQLKQQIENIGNSHIQLAGMLREELKSLEEFRERQKEQRKK-------------------YEAVMERVQKSKVS 117

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662  84 LYKKAMESKKTYEQKCRDADDAEQAFERISANGHQKQVEKSQNKARQCKDSATEAERVYRQSIAQLEKVRAEWEQEHRTT 163
Cdd:cd07671  118 LYKKTMESKKTYEQRCREADEAEQTFERSSSTGNPKQSEKSQNKAKQCRDAATEAERVYKQNIEQLDKARTEWETEHILT 197

                        170       180       190       200
                 ....*....|....*....|....*....|....*....|....*
gi 767985662 164 CEAFQLQEFDRLTILRNALWVHSNQLSMQCVKDDELYEEVRLTLE 208
Cdd:cd07671  198 CEVFQLQEDDRITILRNALWVHCNHFSMQCVKDDELYEEVRTTLE 242

The F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain of Proline-Serine-Threonine Phosphatase-Interacting Protein 1; F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization. Proline-Serine-Threonine Phosphatase-Interacting Protein 1 (PSTPIP1), also known as CD2 Binding Protein 1 (CD2BP1), is mainly expressed in hematopoietic cells. It is a binding partner of the cell surface receptor CD2 and PTP-PEST, a tyrosine phosphatase which functions in cell motility and Rac1 regulation. It also plays a role in the activation of the Wiskott-Aldrich syndrome protein (WASP), which couples actin rearrangement and T cell activation. Mutations in the gene encoding PSTPIP1 cause the autoinflammatory disorder known as PAPA (pyogenic sterile arthritis, pyoderma gangrenosum, and acne) syndrome. PSTPIP1 contains an N-terminal F-BAR domain, PEST motifs, and a C-terminal SH3 domain. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662   4 SLRASFDSLKQQMENVGSSHIQLALTLREELRSLEEFRERQKEQRKKgmavprqsdcmevkspsweYEAVMDRVQKSKLS 83
Cdd:cd07671   57 TLKASFDQLKQQIENIGNSHIQLAGMLREELKSLEEFRERQKEQRKK-------------------YEAVMERVQKSKVS 117

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662  84 LYKKAMESKKTYEQKCRDADDAEQAFERISANGHQKQVEKSQNKARQCKDSATEAERVYRQSIAQLEKVRAEWEQEHRTT 163
Cdd:cd07671  118 LYKKTMESKKTYEQRCREADEAEQTFERSSSTGNPKQSEKSQNKAKQCRDAATEAERVYKQNIEQLDKARTEWETEHILT 197

                        170       180       190       200
                 ....*....|....*....|....*....|....*....|....*
gi 767985662 164 CEAFQLQEFDRLTILRNALWVHSNQLSMQCVKDDELYEEVRLTLE 208
Cdd:cd07671  198 CEVFQLQEDDRITILRNALWVHCNHFSMQCVKDDELYEEVRTTLE 242

Src homology 3 domains; Src homology 3 (SH3) domains bind to target proteins through sequences containing proline and hydrophobic amino acids. Pro-containing polypeptides may bind to SH3 domains in 2 different binding orientations.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|....*.
gi 767985662   311 PAQEYRALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERN-GQRGFVPGSYLE 365
Cdd:smart00326   1 EGPQVRALYDYTAQDPDELSFKKGDIITVLEKSDDGWWKGRLGrGKEGLFPSNYVE 56

MAEBL; Provisional

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662   10 DSLKQQMENVGSSHIQLALTLREELRSLEEFRERQKEQRKKGMAVPRQSDcmevkspsweyEAvmdrvqksklslyKKAM 89
Cdd:PTZ00121 1650 EELKKAEEENKIKAAEEAKKAEEDKKKAEEAKKAEEDEKKAAEALKKEAE-----------EA-------------KKAE 1705

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662   90 ESKKTYEQKCRDADDAEQAFE--RISANGHQKQVEKSQNKARQCKDSATEaervyRQSIAQLEKVRAEWEQEHRTTCEAF 167
Cdd:PTZ00121 1706 ELKKKEAEEKKKAEELKKAEEenKIKAEEAKKEAEEDKKKAEEAKKDEEE-----KKKIAHLKKEEEKKAEEIRKEKEAV 1780

                  ....*..
gi 767985662  168 QLQEFDR 174
Cdd:PTZ00121 1781 IEEELDE 1787

The F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain of Proline-Serine-Threonine Phosphatase-Interacting Protein 1; F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization. Proline-Serine-Threonine Phosphatase-Interacting Protein 1 (PSTPIP1), also known as CD2 Binding Protein 1 (CD2BP1), is mainly expressed in hematopoietic cells. It is a binding partner of the cell surface receptor CD2 and PTP-PEST, a tyrosine phosphatase which functions in cell motility and Rac1 regulation. It also plays a role in the activation of the Wiskott-Aldrich syndrome protein (WASP), which couples actin rearrangement and T cell activation. Mutations in the gene encoding PSTPIP1 cause the autoinflammatory disorder known as PAPA (pyogenic sterile arthritis, pyoderma gangrenosum, and acne) syndrome. PSTPIP1 contains an N-terminal F-BAR domain, PEST motifs, and a C-terminal SH3 domain. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662   4 SLRASFDSLKQQMENVGSSHIQLALTLREELRSLEEFRERQKEQRKKgmavprqsdcmevkspsweYEAVMDRVQKSKLS 83
Cdd:cd07671   57 TLKASFDQLKQQIENIGNSHIQLAGMLREELKSLEEFRERQKEQRKK-------------------YEAVMERVQKSKVS 117

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662  84 LYKKAMESKKTYEQKCRDADDAEQAFERISANGHQKQVEKSQNKARQCKDSATEAERVYRQSIAQLEKVRAEWEQEHRTT 163
Cdd:cd07671  118 LYKKTMESKKTYEQRCREADEAEQTFERSSSTGNPKQSEKSQNKAKQCRDAATEAERVYKQNIEQLDKARTEWETEHILT 197

                        170       180       190       200
                 ....*....|....*....|....*....|....*....|....*
gi 767985662 164 CEAFQLQEFDRLTILRNALWVHSNQLSMQCVKDDELYEEVRLTLE 208
Cdd:cd07671  198 CEVFQLQEDDRITILRNALWVHCNHFSMQCVKDDELYEEVRTTLE 242

The F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain of Proline-Serine-Threonine Phosphatase-Interacting Protein 2; F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization. Proline-Serine-Threonine Phosphatase-Interacting Protein 2 (PSTPIP2), also known as Macrophage Actin-associated tYrosine Phosphorylated protein (MAYP), is mostly expressed in hematopoietic cells but is also expressed in the brain. It is involved in regulating cell adhesion and motility. Mutations in the gene encoding murine PSTPIP2 can cause autoinflammatory disorders such as chronic multifocal osteomyelitis and macrophage autoinflammatory disease. PSTPIP2 contains an N-terminal F-BAR domain and lacks the PEST motifs and SH3 domain that are found in PSTPIP1. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662   3 SSLRASFDSLKQQMENVGSSHIQLALTLREELRSLEEFRERQKEQRKKgmavprqsdcmevkspsweYEAVMDRVQKSKL 82
Cdd:cd07672   57 NTLKRSLDVFKQQIDNVGQSHIQLAQTLRDEAKKMEDFRERQKLARKK-------------------IELIMDAIHKQRA 117

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662  83 SLYKKAMESKKTYEQKCRDADDAEQAFERISANGHQKQVEKSQNKARQCKDSATEAERVYRQSIAQLEKVRAEWEQEHRT 162
Cdd:cd07672  118 MQFKKTMESKKNYEQKCRDKDEAEQAVNRNANLVNVKQQEKLFAKLAQSKQNAEDADRLYMQNISVLDKIREDWQKEHVK 197

                        170       180       190       200
                 ....*....|....*....|....*....|....*....|..
gi 767985662 163 TCEAFQLQEFDRLTILRNALWVHSNQLSMQCVKDDELYEEVR 204
Cdd:cd07672  198 ACEFFEKQECERINFFRNAVWTHVNQLSQQCVTSDEMYEEVR 239

Src homology 3 domains; Src homology 3 (SH3) domains bind to target proteins through sequences containing proline and hydrophobic amino acids. Pro-containing polypeptides may bind to SH3 domains in 2 different binding orientations.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|....*.
gi 767985662   311 PAQEYRALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERN-GQRGFVPGSYLE 365
Cdd:smart00326   1 EGPQVRALYDYTAQDPDELSFKKGDIITVLEKSDDGWWKGRLGrGKEGLFPSNYVE 56

The F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain of Schizosaccharomyces pombe Cdc15, and similar proteins; F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization. This subfamily is composed of Schizosaccharomyces pombe Cdc15 and Imp2, and similar proteins. These proteins contain an N-terminal F-BAR domain and a C-terminal SH3 domain. S. pombe Cdc15 and Imp2 play both distinct and overlapping roles in the maintenance and strengthening of the contractile ring at the division site, which is required in cell division. Cdc15 is a component of the actomyosin ring and is required in normal cytokinesis. Imp2 colocalizes with the medial ring during septation and is required for normal septation. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662   4 SLRASFDSLKQQMENVGSSHIQLALTLREELRS-LEEFRERQKEQRKKgmavprqsdcmevkspsweYEAVMDRVQKSKL 82
Cdd:cd07651   57 GLKNSLDTLRLETESMAKSHLKFAKQIRQDLEEkLAAFASSYTQKRKK-------------------IQSHMEKLLKKKQ 117

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662  83 SLYKKAMESKKTYEQKCRDAddaeQAFERISANGHQKQVEKSQNKARQCKDSATEAERVYRQSIAQLEKVRAEWEQEHRT 162
Cdd:cd07651  118 DQEKYLEKAREKYEADCSKI----NSYTLQSQLTWGKELEKNNAKLNKAQSSINSSRRDYQNAVKALRELNEIWNREWKA 193

                        170       180       190       200
                 ....*....|....*....|....*....|....*....|...
gi 767985662 163 TCEAFQLQEFDRLTILRNALWVHSNQLSMQCVKDDELYEEVRL 205
Cdd:cd07651  194 ALDDFQDLEEERIQFLKSNCWTFANNISTLCVDDDESCERIRS 236

The Extended FES-CIP4 Homology (FCH) or F-BAR (FCH and Bin/Amphiphysin/Rvs) domain, a dimerization module that binds and bends membranes; F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization. F-BAR domain containing proteins, also known as Pombe Cdc15 homology (PCH) family proteins, include Fes and Fer tyrosine kinases, PACSINs/Syndapins, FCHO, PSTPIP, CIP4-like proteins and srGAPs. Many members also contain an SH3 domain and play roles in endocytosis. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules. These tubules have diameters larger than those observed with N-BARs. The F-BAR domains of some members such as NOSTRIN and Rgd1 are important for the subcellular localization of the protein.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662   2 PSSLRASFDSLKQQMENVGSSHIQLALTLREELRSLEEFRERQKEQRKKgmavprqsdcmevkspswEYEAVMDRVQKSK 81
Cdd:cd07610   52 KTSLGTSWNSLREETESAATVHEELSEKLSQLIREPLEKVKEDKEQARK------------------KELAEGEKLKKKL 113

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662  82 LSLYKKAMEskktyeqkcrdaddaeqaferisanghqkqveksqnkarqckdsatEAERVYRQSIAQLEKVRAEWEQEHR 161
Cdd:cd07610  114 QELWAKLAK----------------------------------------------KADEEYREQVEKLNPAQSEYEEEKL 147

                        170       180       190       200
                 ....*....|....*....|....*....|....*....|....
gi 767985662 162 TTCEAFQLQEFDRLTILRNALWVHSNQLSMQCVKDDELYEEVRL 205
Cdd:cd07610  148 NKIQAEQEREEERLEILKDNLKNYINAIKEIPQKIQQELEQSIN 191

SH3 domain; SH3 (Src homology 3) domains are often indicative of a protein involved in signal transduction related to cytoskeletal organization. First described in the Src cytoplasmic tyrosine kinase. The structure is a partly opened beta barrel.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 767985662  316 RALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERN-GQRGFVP 360
Cdd:pfam00018   1 VALYDYTAQEPDELSFKKGDIIIVLEKSEDGWWKGRNKgGKEGLIP 46

Src homology 3 domain of Nitric Oxide Synthase TRaffic INducer; Nostrin is expressed in endothelial and epithelial cells and is involved in the regulation, trafficking and targeting of endothelial NOS (eNOS). It facilitates the endocytosis of eNOS by coordinating the functions of dynamin and the Wiskott-Aldrich syndrome protein (WASP). Increased expression of Nostrin may be correlated to preeclampsia. Nostrin contains an N-terminal F-BAR domain and a C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 767985662 316 RALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERNGQRGFVPGSYLE 365
Cdd:cd11823    3 KALYSYTANREDELSLQPGDIIEVHEKQDDGWWLGELNGKKGIFPATYVE 52

Second C-terminal Src homology 3 domain of Dynamin Binding Protein, also called Tuba, and similar domains; DNMBP or Tuba is a cdc42-specific guanine nucleotide exchange factor (GEF) that contains four N-terminal SH3 domains, a central RhoGEF [or Dbl homology (DH)] domain followed by a Bin/Amphiphysin/Rvs (BAR) domain, and two C-terminal SH3 domains. It provides a functional link between dynamin, Rho GTPase signaling, and actin dynamics. It plays an important role in regulating cell junction configuration. The C-terminal SH3 domains of DNMBP bind to N-WASP and Ena/VASP proteins, which are key regulatory proteins of the actin cytoskeleton. Also included in this subfamily is the second C-terminal SH3 domain of Rho guanine nucleotide exchange factor 37 (ARHGEF37), whose function is still unknown. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 767985662 315 YRALYDYTAQNPDELDLSAGDILEVI----LEGEDGWWTVERNGQRGFVPGSYLEK 366
Cdd:cd11800    2 YYALYTFEARSPGELSVTEGQVVTVLekhdLKGNPEWWLVEDRGKQGYVPSNYLAK 57

First Src homology 3 domain of Tyrosine kinase substrate (Tks) proteins; Tks proteins are Src substrates and scaffolding proteins that play important roles in the formation of podosomes and invadopodia, the dynamic actin-rich structures that are related to cell migration and cancer cell invasion. Vertebrates contain two Tks proteins, Tks4 (Tyr kinase substrate with four SH3 domains) and Tks5 (Tyr kinase substrate with five SH3 domains), which display partially overlapping but non-redundant functions. Both associate with the ADAMs family of transmembrane metalloproteases, which function as sheddases and mediators of cell and matrix interactions. Tks5 interacts with N-WASP and Nck, while Tks4 is essential for the localization of MT1-MMP (membrane-type 1 matrix metalloproteinase) to invadopodia. Tks proteins contain an N-terminal Phox homology (PX) domain and four or five SH3 domains. This model characterizes the first SH3 domain of Tks proteins. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 767985662 314 EYRALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERNGQRGFVPGSYLEK 366
Cdd:cd12015    1 QYVVVADYKKQQPNEISLRAGDVVDVIEKNENGWWFVSLEDEQGWVPATYLEP 53

Src homology 3 domain of Abl Interactor proteins; Abl interactor (Abi) proteins are adaptor proteins serving as binding partners and substrates of Abl tyrosine kinases. They are involved in regulating actin cytoskeletal reorganization and play important roles in membrane-ruffling, endocytosis, cell motility, and cell migration. They localize to sites of actin polymerization in epithelial adherens junction and immune synapses, as well as to the leading edge of lamellipodia. Vertebrates contain two Abi proteins, Abi1 and Abi2. Abi1 displays a wide expression pattern while Abi2 is highly expressed in the eye and brain. Abi proteins contain a homeobox homology domain, a proline-rich region, and a SH3 domain. The SH3 domain of Abi binds to a PxxP motif in Abl. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 767985662 316 RALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERNGQRGFVPGSYLE 365
Cdd:cd11826    3 VALYDYTADKDDELSFQEGDIIYVTKKNDDGWYEGVLNGVTGLFPGNYVE 52

Src Homology 3 domain of Sorting Nexin 9 and similar proteins; Sorting nexins (SNXs) are Phox homology (PX) domain containing proteins that are involved in regulating membrane traffic and protein sorting in the endosomal system. SNXs differ from each other in their lipid-binding specificity, subcellular localization and specific function in the endocytic pathway. This subfamily consists of SH3 domain containing SNXs including SNX9, SNX18, SNX33, and similar proteins. SNX9 is localized to plasma membrane endocytic sites and acts primarily in clathrin-mediated endocytosis, while SNX18 is localized to peripheral endosomal structures, and acts in a trafficking pathway that is clathrin-independent but relies on AP-1 and PACS1. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 767985662 315 YRALYDYTAQNPDELDLSAGDILEVILE-GEDGWWT-VERNGQRGFVPGSYLE 365
Cdd:cd11763    2 VRALYDFDSQPSGELSLRAGEVLTITRQdVGDGWLEgRNSRGEVGLFPSSYVE 54

Src Homology 3 domain of SH3 domain-containing protein 21 (SH3D21) and similar proteins; N-terminal SH3 domain of the uncharacterized protein SH3 domain-containing protein 21, and similar uncharacterized domains, it belongs to the CD2AP-like_3 subfamily of proteins. The CD2AP-like_3 subfamily is composed of the third SH3 domain (SH3C) of CD2AP, CIN85 (Cbl-interacting protein of 85 kDa), and similar domains. CD2AP and CIN85 are adaptor proteins that bind to protein partners and assemble complexes that have been implicated in T cell activation, kidney function, and apoptosis of neuronal cells. They also associate with endocytic proteins, actin cytoskeleton components, and other adaptor proteins involved in receptor tyrosine kinase (RTK) signaling. CD2AP and the main isoform of CIN85 contain three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP and CIN85 to bind various protein partners and assemble complexes that have been implicated in many different functions. SH3C of both proteins have been shown to bind to ubiquitin. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 767985662 315 YRALYDYTAQNPDELDLSAGDILEVILE--GEDGWWTVERNGQRGFVPGSYLE 365
Cdd:cd12142    2 CRVLFDYNPVAPDELALKKGDVIEVISKetEDEGWWEGELNGRRGFFPDNFVM 54

Second Src Homology 3 domain (SH3B) of CD2-associated protein and similar proteins; This subfamily is composed of the second SH3 domain (SH3B) of CD2AP, CIN85 (Cbl-interacting protein of 85 kDa), and similar domains. CD2AP and CIN85 are adaptor proteins that bind to protein partners and assemble complexes that have been implicated in T cell activation, kidney function, and apoptosis of neuronal cells. They also associate with endocytic proteins, actin cytoskeleton components, and other adaptor proteins involved in receptor tyrosine kinase (RTK) signaling. CD2AP and the main isoform of CIN85 contain three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP and CIN85 to bind various protein partners and assemble complexes that have been implicated in many different functions. SH3B of both proteins have been shown to bind to Cbl. In the case of CD2AP, its SH3B binds to Cbl at a site distinct from the c-Cbl/SH3A binding site. The CIN85 SH3B also binds ubiquitin. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 767985662 316 RALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERNGQRGFVPGSYLE 365
Cdd:cd11874    3 KVLFSYTPQNEDELELKVGDTIEVLGEVEEGWWEGKLNGKVGVFPSNFVK 52

Src homology 3 domain of CAS (Crk-Associated Substrate) scaffolding proteins; CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes including migration, chemotaxis, apoptosis, differentiation, and progenitor cell function. They mediate the signaling of integrins at focal adhesions where they localize, and thus, regulate cell invasion and survival. Over-expression of these proteins is implicated in poor prognosis, increased metastasis, and resistance to chemotherapeutics in many cancers such as breast, lung, melanoma, and glioblastoma. CAS proteins have also been linked to the pathogenesis of inflammatory disorders, Alzheimer's, Parkinson's, and developmental defects. They share a common domain structure that includes an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain. Vertebrates contain four CAS proteins: BCAR1 (or p130Cas), NEDD9 (or HEF1), EFS (or SIN), and CASS4 (or HEPL). The SH3 domain of CAS proteins binds to diverse partners including FAK, FRNK, Pyk2, PTP-PEST, DOCK180, among others. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 767985662 316 RALYDYTAQNPDELDLSAGDILEVI---LEGEDGWWTVERNGQRGFVPGSYLE 365
Cdd:cd11844    3 RALYDNVAESPDELAFRRGDILTVLeqnTAGLEGWWLCSLRGRQGIAPGNRLK 55

First Src Homology 3 domain (SH3A) of CD2-associated protein and similar proteins; This subfamily is composed of the first SH3 domain (SH3A) of CD2AP, CIN85 (Cbl-interacting protein of 85 kDa), and similar domains. CD2AP and CIN85 are adaptor proteins that bind to protein partners and assemble complexes that have been implicated in T cell activation, kidney function, and apoptosis of neuronal cells. They also associate with endocytic proteins, actin cytoskeleton components, and other adaptor proteins involved in receptor tyrosine kinase (RTK) signaling. CD2AP and the main isoform of CIN85 contain three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP and CIN85 to bind various protein partners and assemble complexes that have been implicated in many different functions. SH3A of both proteins bind to an atypical PXXXPR motif at the C-terminus of Cbl and the cytoplasmic domain of the cell adhesion protein CD2. CIN85 SH3A binds to internal proline-rich motifs within the proline-rich region; this intramolecular interaction serves as a regulatory mechanism to keep CIN85 in a closed conformation, preventing the recruitment of other proteins. CIN85 SH3A has also been shown to bind ubiquitin. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 767985662 314 EYRALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERNGQRGFVPGSYLEK 366
Cdd:cd11873    1 EVIVEFDYDAEEPDELTLKVGDIITNVKKMEEGWWEGTLNGKRGMFPDNFVKV 53

Third Src Homology 3 domain (SH3C) of CD2-associated protein and similar proteins; This subfamily is composed of the third SH3 domain (SH3C) of CD2AP, CIN85 (Cbl-interacting protein of 85 kDa), and similar domains. CD2AP and CIN85 are adaptor proteins that bind to protein partners and assemble complexes that have been implicated in T cell activation, kidney function, and apoptosis of neuronal cells. They also associate with endocytic proteins, actin cytoskeleton components, and other adaptor proteins involved in receptor tyrosine kinase (RTK) signaling. CD2AP and the main isoform of CIN85 contain three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP and CIN85 to bind various protein partners and assemble complexes that have been implicated in many different functions. SH3C of both proteins have been shown to bind to ubiquitin. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 767985662 315 YRALYDYTAQNPDELDLSAGDILEVILE--GEDGWWTVERNGQRGFVPGSYLE 365
Cdd:cd11875    2 ARVLFDYEAENEDELTLREGDIVTILSKdcEDKGWWKGELNGKRGVFPDNFVE 54

C-terminal Src Homology 3 domain of LIM and SH3 domain protein 1; Lasp1 is a cytoplasmic protein that binds focal adhesion proteins and is involved in cell signaling, migration, and proliferation. It is overexpressed in several cancer cells including breast, ovarian, bladder, and liver. In cancer cells, it can be found in the nucleus; its degree of nuclear localization correlates with tumor size and poor prognosis. Lasp1 is a 36kD protein containing an N-terminal LIM domain, two nebulin repeats, and a C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*...
gi 767985662 312 AQEYRALYDYTAQNPDELDLSAGDILEVILEGEDGWW--TVERNGQRGFVPGSYLEKL 367
Cdd:cd11934    2 GKRYRAVYDYNAADEDEVSFQDGDTIVNVQQIDDGWMygTVERTGDTGMLPANYVEAI 59

Src homology 3 domain of Alpha Spectrin; Spectrin is a major structural component of the red blood cell membrane skeleton and is important in erythropoiesis and membrane biogenesis. It is a flexible, rope-like molecule composed of two subunits, alpha and beta, which consist of many spectrin-type repeats. Alpha and beta spectrin associate to form heterodimers and tetramers; spectrin tetramer formation is critical for red cell shape and deformability. Defects in alpha spectrin have been associated with inherited hemolytic anemias including hereditary spherocytosis (HSp), hereditary elliptocytosis (HE), and hereditary pyropoikilocytosis (HPP). Alpha spectrin contains a middle SH3 domain and a C-terminal EF-hand binding motif in addition to multiple spectrin repeats. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 767985662 317 ALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERNGQRGFVPGSYLEK 366
Cdd:cd11808    4 ALYDYQEKSPREVSMKKGDILTLLNSSNKDWWKVEVNDRQGFVPAAYVKK 53

The F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain of FCH domain Only 2 protein; F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization. The specific function of FCH domain Only 2 (FCHO2) is still unknown. It contains an N-terminal F-BAR domain and a C-terminal domain of unknown function named SAFF which is also present in FCHO1 and endophilin interacting protein 1. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662   9 FDSLKQQMENVGSSHIQLALTLREELRSLEEFRERQKEQRKKGMAvprqsdcmevkspswEYEAVMDRVQKSKlSLYKKA 88
Cdd:cd07673   69 WDVFKTSTEKLANCHLELVRKLQELIKEVQKYGEEQVKSHKKTKE---------------EVAGTLEAVQNIQ-SITQAL 132

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767985662  89 MESKKTYEQKCrdaddAEQafERISANG-HQKQVEKSQNKARQckdsATEAERVYRQSIAQlekVRAEWEQEHRTTCEAF 167
Cdd:cd07673  133 QKSKENYNAKC-----LEQ--ERLKKEGaTQREIEKAAVKSKK----ATESYKLYVEKYAL---AKADFEQKMTETAQKF 198

                        170       180       190       200       210       220
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 767985662 168 QLQEFDRLTILRNALWVHSNQLSMQCVKDDELYEEVRLTLEGCSIDADIDSFIQAKSTGTEPPAPVPYQ 236
Cdd:cd07673  199 QDIEETHLIRIKEIIGSYSNSVKEIHIQIGQVHEEFINNMANTTVESLIQKFAESKGTGKERPGPIEFE 267

C-terminal Src Homology 3 domain of Nebulette and LIM-nebulette (or Lasp2); Nebulette is a cardiac-specific protein that localizes to the Z-disc. It interacts with tropomyosin and is important in stabilizing actin thin filaments in cardiac muscles. Polymorphisms in the nebulette gene are associated with dilated cardiomyopathy, with some mutations resulting in severe heart failure. Nebulette is a 107kD protein that contains an N-terminal acidic region, multiple nebulin repeats, and a C-terminal SH3 domain. LIM-nebulette, also called Lasp2 (LIM and SH3 domain protein 2), is an alternatively spliced variant of nebulette. Although it shares a gene with nebulette, Lasp2 is not transcribed from a muscle-specific promoter, giving rise to its multiple tissue expression pattern with highest amounts in the brain. It can crosslink actin filaments and it affects cell spreading. Lasp2 is a 34kD protein containing an N-terminal LIM domain, three nebulin repeats, and a C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 767985662 315 YRALYDYTAQNPDELDLSAGDILEVILEGEDGWW--TVERNGQRGFVPGSYLE 365
Cdd:cd11935    3 YRAMYDYSAQDEDEVSFRDGDYIVNVQPIDEGWMygTVQRTGRTGMLPANYIE 55

Third Src Homology 3 domain of the fungal endocytic adaptor protein Sla1p; Sla1p facilitates endocytosis by playing a role as an adaptor protein in coupling components of the actin cytoskeleton to the endocytic machinery. It interacts with Abp1p, Las17p and Pan1p, which are activator proteins of actin-related protein 2/3 (Arp2/3). Sla1p contains multiple domains including three SH3 domains, a SAM (sterile alpha motif) domain, and a Sla1 homology domain 1 (SHD1), which binds to the NPFXD motif that is found in many integral membrane proteins such as the Golgi-localized Arf-binding protein Lsb5p and the P4-ATPases, Drs2p and Dnf1p. The third SH3 domain of Sla1p can bind ubiquitin while retaining the ability to bind proline-rich ligands; monoubiquitination of target proteins signals internalization and sorting through the endocytic pathway. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 767985662 316 RALYDYTAQNPDELDLSAGDILeVILEGE--DGWWTVER--NGQRGFVPGSYLE 365
Cdd:cd11775    4 KVLYDFDAQSDDELTVKEGDVV-YILDDKksKDWWMVENvsTGKEGVVPASYIE 56

Src Homology 3 domain of Cdc42-Interacting Protein 4; This subfamily is composed of Cdc42-Interacting Protein 4 (CIP4), Formin Binding Protein 17 (FBP17), FormiN Binding Protein 1-Like (FNBP1L), and similar proteins. CIP4 and FNBP1L are Cdc42 effectors that bind Wiskott-Aldrich syndrome protein (WASP) and function in endocytosis. CIP4 and FBP17 bind to the Fas ligand and may be implicated in the inflammatory response. CIP4 may also play a role in phagocytosis. It functions downstream of Cdc42 in PDGF-dependent actin reorganization and cell migration, and also regulates the activity of PDGFRbeta. It uses Src as a substrate in regulating the invasiveness of breast tumor cells. CIP4 may also play a role in the pathogenesis of Huntington's disease. Members of this subfamily typically contain an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain, a central Cdc42-binding HR1 domain, and a C-terminal SH3 domain. The SH3 domain of CIP4 associates with Gapex-5, a Rab31 GEF. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 767985662 316 RALYDYTAQNPDELDLSAGDILEVILE-GEDGWWTVERN-GQRGFVPGSYLE 365
Cdd:cd11911    3 TALYDFDGTSEGTLSMEEGEILLVLEEdGGDGWTRVRKNnGDEGYVPTSYIE 54

Second or C-terminal Src homology 3 domain of the p47phox subunit of NADPH oxidase, also called Neutrophil Cytosolic Factor 1; p47phox, or NCF1, is a cytosolic subunit of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox), which plays a key role in the ability of phagocytes to defend against bacterial infections. NADPH oxidase catalyzes the transfer of electrons from NADPH to oxygen during phagocytosis forming superoxide and reactive oxygen species. p47phox is required for activation of NADH oxidase and plays a role in translocation. It contains an N-terminal Phox homology (PX) domain, tandem SH3 domains (N-SH3 and C-SH3), a polybasic/autoinhibitory region, and a C-terminal proline-rich region (PRR). This model characterizes the second SH3 domain (or C-SH3) of p47phox. In its inactive state, the tandem SH3 domains interact intramolecularly with the autoinhibitory region; upon activation, the tandem SH3 domains are exposed through a conformational change, resulting in their binding to the PRR of p22phox and the activation of NADPH oxidase. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 767985662 315 YRALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERNGQRGFVPGSYLEK 366
Cdd:cd12022    2 YITIKAYTAVEEDELTLLEGEAIEVIHKLLDGWWVVRKGEVTGYFPSMYLQK 53

Src homology 3 domain of Endophilin-A; Endophilins play roles in synaptic vesicle formation, virus budding, mitochondrial morphology maintenance, receptor-mediated endocytosis inhibition, and endosomal sorting. They are classified into two types, A and B. Vertebrates contain three endophilin-A isoforms (A1, A2, and A3). Endophilin-A proteins are enriched in the brain and play multiple roles in receptor-mediated endocytosis. They tubulate membranes and regulate calcium influx into neurons to trigger the activation of the endocytic machinery. They are also involved in the sorting of plasma membrane proteins, actin filament assembly, and the uncoating of clathrin-coated vesicles for fusion with endosomes. Endophilins contain an N-terminal N-BAR domain (BAR domain with an additional N-terminal amphipathic helix), followed by a variable region containing proline clusters, and a C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 767985662 315 YRALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERNGQRGFVPGSYLE 365
Cdd:cd11803    3 CRALYDFEPENEGELGFKEGDIITLTNQIDENWYEGMVNGQSGFFPVNYVE 53

First Src homology 3 domain (or SH3A) of Intersectin; Intersectins (ITSNs) are adaptor proteins that function in exo- and endocytosis, actin cytoskeletal reorganization, and signal transduction. They are essential for initiating clathrin-coated pit formation. They bind to many proteins through their multidomain structure and facilitate the assembly of multimeric complexes. Vertebrates contain two ITSN proteins, ITSN1 and ITSN2, which exist in alternatively spliced short and long isoforms. The short isoforms contain two Eps15 homology domains (EH1 and EH2), a coiled-coil region and five SH3 domains (SH3A-E), while the long isoforms, in addition, contain RhoGEF (also called Dbl-homologous or DH), Pleckstrin homology (PH) and C2 domains. ITSN1 and ITSN2 are both widely expressed, with variations depending on tissue type and stage of development. The first SH3 domain (or SH3A) of ITSN1 has been shown to bind many proteins including Sos1, dynamin1/2, CIN85, c-Cbl, PI3K-C2, SHIP2, N-WASP, and CdGAP, among others. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 767985662 315 YRALYDYTAQNPDELDLSAGDILEVILE--GEDGWWTVERNGQRGFVPGSYLEK 366
Cdd:cd11836    2 YRALYAFEARNPDEISFQPGDIIQVDESqvAEPGWLAGELKGKTGWFPANYVEK 55

Src homology 3 domain of the CAS (Crk-Associated Substrate) scaffolding protein family member, Breast Cancer Anti-estrogen Resistance 1; BCAR1, also called p130cas or CASS1, is the founding member of the CAS family of scaffolding proteins and was originally identified through its ability to associate with Crk. The name BCAR1 was designated because the human gene was identified in a screen for genes that promote resistance to tamoxifen. It is widely expressed and its deletion is lethal in mice. It plays a role in regulating cell motility, survival, proliferation, transformation, cancer progression, and bacterial pathogenesis. CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes. They share a common domain structure that includes an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain. The SH3 domain of CAS proteins binds to diverse partners including FAK, FRNK, Pyk2, PTP-PEST, DOCK180, among others. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 767985662 316 RALYDYTAQNPDELDLSAGDILEVI---LEGEDGWWTVERNGQRGFVPGSYLEKL 367
Cdd:cd12001    6 KALYDNVAESPDELSFRKGDIMTVLerdTQGLDGWWLCSLHGRQGIVPGNRLKIL 60

First Src Homology 3 domain of the fungal endocytic adaptor protein Sla1p; Sla1p facilitates endocytosis by playing a role as an adaptor protein in coupling components of the actin cytoskeleton to the endocytic machinery. It interacts with Abp1p, Las17p and Pan1p, which are activator proteins of actin-related protein 2/3 (Arp2/3). Sla1p contains multiple domains including three SH3 domains, a SAM (sterile alpha motif) domain, and a Sla1 homology domain 1 (SHD1), which binds to the NPFXD motif that is found in many integral membrane proteins such as the Golgi-localized Arf-binding protein Lsb5p and the P4-ATPases, Drs2p and Dnf1p. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 767985662 315 YRALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERN-------GQRGFVPGSY 363
Cdd:cd11773    2 YKALYDYEPQTEDELTIQEDDILYLLEKSDDDWWKVKLKvnssdddEPVGLVPATY 57

Second Src Homology 3 domain of Bzz1 and similar domains; Bzz1 (or Bzz1p) is a WASP/Las17-interacting protein involved in endocytosis and trafficking to the vacuole. It physically interacts with type I myosins and functions in the early steps of endocytosis. Together with other proteins, it induces membrane scission in yeast. Bzz1 contains an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs), a central coiled-coil, and two C-terminal SH3 domains. This model represents the second C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 767985662 317 ALYDYTAQNPDELDLSAGDILEVIlEGED--GWWTVERNGQRGFVPGSY 363
Cdd:cd11778    4 ALYDYEAQGDDEISIRVGDRIAVI-RGDDgsGWTYGEINGVKGLFPTSY 51

First Src homology 3 domain of Tyrosine kinase substrate with five SH3 domains; Tks5, also called SH3 and PX domain-containing protein 2A (SH3PXD2A) or Five SH (FISH), is a scaffolding protein and Src substrate that is localized in podosomes, which are electron-dense structures found in Src-transformed fibroblasts, osteoclasts, macrophages, and some invasive cancer cells. It binds and regulates some members of the ADAMs family of transmembrane metalloproteases, which function as sheddases and mediators of cell and matrix interactions. It is required for podosome formation, degradation of the extracellular matrix, and cancer cell invasion. Tks5 contains an N-terminal Phox homology (PX) domain and five SH3 domains. This model characterizes the first SH3 domain of Tks5. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 767985662 314 EYRALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERNGQRGFVPGSYLE 365
Cdd:cd12074    1 QYVVVSNYEKQENSEISLQAGEVVDVIEKNESGWWFVSTAEEQGWVPATYLE 52

Fifth Src homology 3 domain (or SH3E) of Intersectin-1; Intersectin-1 (ITSN1) is an adaptor protein that functions in exo- and endocytosis, actin cytoskeletal reorganization, and signal transduction. It plays a role in clathrin-coated pit (CCP) formation. It binds to many proteins through its multidomain structure and facilitate the assembly of multimeric complexes. ITSN1 localizes in membranous organelles, CCPs, the Golgi complex, and may be involved in the cell membrane trafficking system. It exists in alternatively spliced short and long isoforms. The short isoform contains two Eps15 homology domains (EH1 and EH2), a coiled-coil region and five SH3 domains (SH3A-E), while the long isoform, in addition, contains RhoGEF (also called Dbl-homologous or DH), Pleckstrin homology (PH) and C2 domains. The fifth SH3 domain (or SH3E) of ITSN1 has been shown to bind many protein partners including SGIP1, Sos1, dynamin1/2, CIN85, c-Cbl, SHIP2, N-WASP, and synaptojanin-1, among others. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 767985662 317 ALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERNGQRGFVPGSYLE 365
Cdd:cd11995    5 GMYDYTAQNDDELAFSKGQIINVLNKEDPDWWKGELNGQVGLFPSNYVK 53

Src homology 3 domain of Cortactin and related proteins; This subfamily includes cortactin, Abp1 (actin-binding protein 1), hematopoietic lineage cell-specific protein 1 (HS1), and similar proteins. These proteins are involved in regulating actin dynamics through direct or indirect interaction with the Arp2/3 complex, which is required to initiate actin polymerization. They all contain at least one C-terminal SH3 domain. Cortactin and HS1 bind Arp2/3 and actin through an N-terminal region that contains an acidic domain and several copies of a repeat domain found in cortactin and HS1. Abp1 binds actin via an N-terminal actin-depolymerizing factor (ADF) homology domain. Yeast Abp1 binds Arp2/3 directly through two acidic domains. Mammalian Abp1 does not directly interact with Arp2/3; instead, it regulates actin dynamics indirectly by interacting with dynamin and WASP family proteins. The C-terminal region of these proteins acts as an adaptor or scaffold that can connect membrane trafficking and signaling proteins that bind the SH3 domain within the actin network. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 767985662 316 RALYDYTAQNPDELDLSAGDILEVILEGEDGWWT-VERNGQRGFVPGSYLE 365
Cdd:cd11819    3 KALYDYQAAEDNEISFVEGDIITQIEQIDEGWWLgVNAKGQKGLFPANYVE 53

N-terminal Src homology 3 domain of Growth factor receptor-bound protein 2 (GRB2) and related proteins; This family includes the adaptor protein GRB2 and related proteins including Drosophila melanogaster Downstream of receptor kinase (DRK), Caenorhabditis elegans Sex muscle abnormal protein 5 (Sem-5), GRB2-related adaptor protein (GRAP), GRAP2, and similar proteins. Family members contain an N-terminal SH3 domain, a central SH2 domain, and a C-terminal SH3 domain. GRB2/Sem-5/DRK is a critical signaling molecule that regulates the Ras pathway by linking tyrosine kinases to the Ras guanine nucleotide releasing protein Sos (son of sevenless), which converts Ras to the active GTP-bound state. GRAP2 plays an important role in T cell receptor (TCR) signaling by promoting the formation of the SLP-76:LAT complex, which couples the TCR to the Ras pathway. GRAP acts as a negative regulator of T cell receptor (TCR)-induced lymphocyte proliferation by downregulating the signaling to the Ras/ERK pathway. The N-terminal SH3 domain of GRB2 binds to Sos and Sos-derived proline-rich peptides. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 767985662 314 EYRALYDYTAQNPDELDLSAGDILEVILEGED-GWWTVERNGQRGFVPGSYL 364
Cdd:cd11804    1 EAVAKHDFKATAEDELSFKKGSILKVLNMEDDpNWYKAELDGKEGLIPKNYI 52

Src homology 3 domain of Protein arginine N-methyltransferase 2; PRMT2, also called HRMT1L1, belongs to the arginine methyltransferase protein family. It functions as a coactivator to both estrogen receptor alpha (ER-alpha) and androgen receptor (AR), presumably through arginine methylation. The ER-alpha transcription factor is involved in cell proliferation, differentiation, morphogenesis, and apoptosis, and is also implicated in the development and progression of breast cancer. PRMT2 and its variants are upregulated in breast cancer cells and may be involved in modulating the ER-alpha signaling pathway during formation of breast cancer. PRMT2 also plays a role in regulating the function of E2F transcription factors, which are critical cell cycle regulators, by binding to the retinoblastoma gene product (RB). It contains an N-terminal SH3 domain and an AdoMet binding domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 767985662 314 EYRALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERNGQRGFVPGSYL 364
Cdd:cd11806    1 EYVAIADFVATDDSQLSFESGDKLLVLRKPSVDWWWAEHNGCCGYIPASHL 51

Second Src homology 3 domain of Tyrosine kinase substrate (Tks) proteins; Tks proteins are Src substrates and scaffolding proteins that play important roles in the formation of podosomes and invadopodia, the dynamic actin-rich structures that are related to cell migration and cancer cell invasion. Vertebrates contain two Tks proteins, Tks4 (Tyr kinase substrate with four SH3 domains) and Tks5 (Tyr kinase substrate with five SH3 domains), which display partially overlapping but non-redundant functions. Both associate with the ADAMs family of transmembrane metalloproteases, which function as sheddases and mediators of cell and matrix interactions. Tks5 interacts with N-WASP and Nck, while Tks4 is essential for the localization of MT1-MMP (membrane-type 1 matrix metalloproteinase) to invadopodia. Tks proteins contain an N-terminal Phox homology (PX) domain and four or five SH3 domains. This model characterizes the second SH3 domain of Tks proteins. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 767985662 313 QEYRALYDYTAQNPDELDLSAGDILEVILEGEDGWWTVERNGQRGFVPGSYLEK 366
Cdd:cd12016    1 EKYITTQAYKAENEDEIGFETGVVVEVIQKNLDGWWKIRYQGKEGWAPATYLKK 54

Src homology 3 domain of Protein kinase C and Casein kinase Substrate in Neurons (PACSIN) proteins; PACSINs, also called Synaptic dynamin-associated proteins (Syndapins), act as regulators of cytoskeletal and membrane dynamics. They bind both dynamin and Wiskott-Aldrich syndrome protein (WASP), and may provide direct links between the actin cytoskeletal machinery through WASP and dynamin-dependent endocytosis. Vetebrates harbor three isoforms with distinct expression patterns and specific functions. PACSINs contain an N-terminal F-BAR domain and a C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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                 ....*....|....*....|....*....|....*....|....*....|.
gi 767985662 316 RALYDYTAQNPDELDLSAGDILEVIL-EGEDGWWTVERNGQRGFVPGSYLE 365
Cdd:cd11843    3 RALYDYEGQESDELSFKAGDILTKLEeEDEQGWCKGRLDGRVGLYPANYVE 53