CHY zinc finger; This family of domains are likely to bind to zinc ions. They contain many conserved cysteine and histidine residues. We have named this domain after the N-terminal motif CXHY. This domain can be found in isolation in some proteins, but is also often associated with pfam00097. One of the proteins in this family is a mitochondrial intermembrane space protein called Hot13. This protein is involved in the assembly of small TIM complexes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1002231267  61 CAHYRRRCRIRAPCCNEIFDCRHCHNETKNSikidavkrHELPRHEVQQVICSLCGTEQEVRQVCISCGVCMGKYFCEVC 140
Cdd:pfam05495   1 CKHYHRNCKLRCPCCGKWYPCRLCHDEVEDE--------HPLDRYAVTEMLCMLCDTEQPVAVLCGNCGVTFAEYFCPIC 72

                  ...
gi 1002231267 141 KLF 143
Cdd:pfam05495  73 KLY 75

RING finger (Really Interesting New Gene) domain and U-box domain superfamily; The RING finger is a specialized type of Zn-finger of 40 to 60 residues that binds two atoms of zinc. It is defined by the "cross-brace" motif that chelates zinc atoms by eight amino acid residues, typically Cys or His, arranged in a characteristic spacing. Canonical RING motifs have been categorized into two major subclasses, RING-HC (C3HC4-type) and RING-H2 (C3H2C3-type), according to their Cys/His content. There are also many variants of RING fingers: some have different Cys/His patterns while some lack a single Cys or His residue at typical Zn ligand positions (the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can indeed chelate Zn in a RING finger as well). C4C4-, C3HC3D-, C2H2C4-, and C3HC5-type RING fingers are closely related to RING-HC fingers. In contrast, C4HC3- (RING-CH alias RINGv), C3H3C2-, C3H2C2D-, C3DHC3-, and C4HC2H-type RING fingers are more closely related to RING-H2 fingers. However, not all RING finger-containing proteins display regular RING finger features, and the RING finger family has turned out to be multifarious. The degenerate RING fingers of the Siz/PIAS RING (SP-RING) family proteins and sporulation protein RMD5, are characterized by lacking the second, fifth, and sixth Zn2+ ion-coordinating residues. They bind only one Zn2+ ion. On the other hand, the RING fingers of the human APC11 and RBX1 proteins can bind a third Zn atom since they harbor four additional Zn ligands. U-box is a modified form of the RING finger domain that lacks metal chelating Cys and His residues. It resembles the cross-brace RING structure consisting of three beta-sheets and a single alpha-helix, which would be stabilized by salt bridges instead of chelated metal ions. U-box proteins are widely distributed among eukaryotic organisms and show a higher prevalence in plants than in other organisms. RING finger/U-box-containing proteins are a group of diverse proteins with a variety of cellular functions, including oncogenesis, development, viral replication, signal transduction, the cell cycle and apoptosis. Many of them are ubiquitin-protein ligases (E3s) that serve as scaffolds for binding to ubiquitin-conjugating enzymes (E2s, also referred to as ubiquitin carrier proteins or UBCs) in close proximity to substrate proteins, which enable efficient transfer of ubiquitin from E2 to the substrates.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 1002231267 196 DCPICFEYLFESTNDVSVLPCGHTIHVKCLREMEEHCQFACPLCS 240
Cdd:cd16464     1 NCPVCLEDLFTSREPVHVLPCGHLMHSTCFEEYLKSGNYRCPLCS 45

CHY zinc finger; This family of domains are likely to bind to zinc ions. They contain many conserved cysteine and histidine residues. We have named this domain after the N-terminal motif CXHY. This domain can be found in isolation in some proteins, but is also often associated with pfam00097. One of the proteins in this family is a mitochondrial intermembrane space protein called Hot13. This protein is involved in the assembly of small TIM complexes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1002231267  61 CAHYRRRCRIRAPCCNEIFDCRHCHNETKNSikidavkrHELPRHEVQQVICSLCGTEQEVRQVCISCGVCMGKYFCEVC 140
Cdd:pfam05495   1 CKHYHRNCKLRCPCCGKWYPCRLCHDEVEDE--------HPLDRYAVTEMLCMLCDTEQPVAVLCGNCGVTFAEYFCPIC 72

                  ...
gi 1002231267 141 KLF 143
Cdd:pfam05495  73 KLY 75

RING finger, H2 subclass, found in p53-induced RING-H2 protein (Pirh2) and similar proteins; Pirh2, also known as RING finger and CHY zinc finger domain-containing protein 1 (Rchy1), androgen receptor N-terminal-interacting protein, CH-rich-interacting match with PLAG1, RING finger protein 199 (RNF199), or zinc finger protein 363 (ZNF363), is a p53 inducible E3 ubiquitin-protein ligase that functions as a negative regulator of p53. It preferably ubiquitylates the tetrameric form of p53 in vitro and in vivo, suggesting a role of Pirh2 in downregulating the transcriptionally active form of p53 in the cell. Moreover, Pirh2 inhibits the transcriptional activity of p73, a homolog of the tumor suppressor p53, by promoting its ubiquitination. It also monoubiquitinates DNA polymerase eta (PolH) to suppress translesion DNA synthesis. Furthermore, Pirh2 functions as a negative regulator of the cyclin-dependent kinase inhibitor p27(Kip1) function by promoting ubiquitin-dependent proteasomal degradation. Pirh2 enhances androgen receptor (AR) signaling through inhibition of histone deacetylase 1 (HDAC1) and is overexpressed in prostate cancer. It interacts with TIP60 and this association may regulate Pirh2 stability. In addition, the oncoprotein pleomorphic adenoma gene like 2 (PLAGL2) can bind to the Pirh2 dimer and therefore control the stability of Pirh2. Pirh2 contains a total of nine zinc-binding sites with six located at the N-terminal region, two in the C3H2C3-type RING-H2 domain, and one in the C-terminal region. Nine zinc binding sites comprise three different zinc coordination schemes, including RING type cross-brace zinc coordination, C4 zinc finger, and a novel left-handed beta-spiral zinc-binding motif formed by three recurrent CCHC sequence motifs. This subfamily also includes Drosophila melanogaster Deltex, a ubiquitously expressed cytoplasmic ubiquitin E3 ligase that mediates Notch activation in Drosophila. It selectively suppresses T-cell activation through degradation of a key signaling molecule, MAP kinase kinase kinase 1 (MEKK1). It also inhibits Jun-mediated transcription at the stage of Ras-dependent Jun N-terminal protein kinase (JNK) activation. Deltex contains N-terminal two Notch-binding WWE domains that physically interact with the Notch ankyrin domains, a proline-rich motif that shares homology with SH3-binding domains, and a RING finger at the C-terminus.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 1002231267 196 DCPICFEYLFESTNDVSVLPCGHTIHVKCLREMEEHCQFACPLCS 240
Cdd:cd16464     1 NCPVCLEDLFTSREPVHVLPCGHLMHSTCFEEYLKSGNYRCPLCS 45

Ring finger; E3 ubiquitin-protein ligase activity is intrinsic to the RING domain of c-Cbl and is likely to be a general function of this domain; Various RING fingers exhibit binding activity towards E2 ubiquitin-conjugating enzymes (Ubc' s)

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|...
gi 1002231267  197 CPICFEYLFEstnDVSVLPCGHTIHVKCLREMEEHCQFACPLC 239
Cdd:smart00184   1 CPICLEEYLK---DPVILPCGHTFCRSCIRKWLESGNNTCPIC 40

CHY zinc finger; This family of domains are likely to bind to zinc ions. They contain many conserved cysteine and histidine residues. We have named this domain after the N-terminal motif CXHY. This domain can be found in isolation in some proteins, but is also often associated with pfam00097. One of the proteins in this family is a mitochondrial intermembrane space protein called Hot13. This protein is involved in the assembly of small TIM complexes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1002231267  61 CAHYRRRCRIRAPCCNEIFDCRHCHNETKNSikidavkrHELPRHEVQQVICSLCGTEQEVRQVCISCGVCMGKYFCEVC 140
Cdd:pfam05495   1 CKHYHRNCKLRCPCCGKWYPCRLCHDEVEDE--------HPLDRYAVTEMLCMLCDTEQPVAVLCGNCGVTFAEYFCPIC 72

                  ...
gi 1002231267 141 KLF 143
Cdd:pfam05495  73 KLY 75

RING finger, H2 subclass, found in p53-induced RING-H2 protein (Pirh2) and similar proteins; Pirh2, also known as RING finger and CHY zinc finger domain-containing protein 1 (Rchy1), androgen receptor N-terminal-interacting protein, CH-rich-interacting match with PLAG1, RING finger protein 199 (RNF199), or zinc finger protein 363 (ZNF363), is a p53 inducible E3 ubiquitin-protein ligase that functions as a negative regulator of p53. It preferably ubiquitylates the tetrameric form of p53 in vitro and in vivo, suggesting a role of Pirh2 in downregulating the transcriptionally active form of p53 in the cell. Moreover, Pirh2 inhibits the transcriptional activity of p73, a homolog of the tumor suppressor p53, by promoting its ubiquitination. It also monoubiquitinates DNA polymerase eta (PolH) to suppress translesion DNA synthesis. Furthermore, Pirh2 functions as a negative regulator of the cyclin-dependent kinase inhibitor p27(Kip1) function by promoting ubiquitin-dependent proteasomal degradation. Pirh2 enhances androgen receptor (AR) signaling through inhibition of histone deacetylase 1 (HDAC1) and is overexpressed in prostate cancer. It interacts with TIP60 and this association may regulate Pirh2 stability. In addition, the oncoprotein pleomorphic adenoma gene like 2 (PLAGL2) can bind to the Pirh2 dimer and therefore control the stability of Pirh2. Pirh2 contains a total of nine zinc-binding sites with six located at the N-terminal region, two in the C3H2C3-type RING-H2 domain, and one in the C-terminal region. Nine zinc binding sites comprise three different zinc coordination schemes, including RING type cross-brace zinc coordination, C4 zinc finger, and a novel left-handed beta-spiral zinc-binding motif formed by three recurrent CCHC sequence motifs. This subfamily also includes Drosophila melanogaster Deltex, a ubiquitously expressed cytoplasmic ubiquitin E3 ligase that mediates Notch activation in Drosophila. It selectively suppresses T-cell activation through degradation of a key signaling molecule, MAP kinase kinase kinase 1 (MEKK1). It also inhibits Jun-mediated transcription at the stage of Ras-dependent Jun N-terminal protein kinase (JNK) activation. Deltex contains N-terminal two Notch-binding WWE domains that physically interact with the Notch ankyrin domains, a proline-rich motif that shares homology with SH3-binding domains, and a RING finger at the C-terminus.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 1002231267 196 DCPICFEYLFESTNDVSVLPCGHTIHVKCLREMEEHCQFACPLCS 240
Cdd:cd16464     1 NCPVCLEDLFTSREPVHVLPCGHLMHSTCFEEYLKSGNYRCPLCS 45

H2 subclass of RING (RING-H2) fingers and its variants; The RING finger is a specialized type of Zn-finger of 40 to 60 residues that binds two atoms of zinc. It is defined by the "cross-brace" motif that chelates zinc atoms by eight amino acid residues, typically Cys or His, arranged in a characteristic spacing. Canonical RING motifs have been categorized into two major subclasses, RING-HC (C3HC4-type) and RING-H2 (C3H2C3-type), according to their Cys/His content. There are also many variants of RING fingers: some have different Cys/His patterns while some lack a single Cys or His residue at typical Zn ligand positions (the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can indeed chelate Zn in a RING finger as well). This family corresponds to the H2 subclass of RING (RING-H2) finger proteins that are characterized by containing C3H2C3-type canonical RING-H2 fingers or noncanonical RING-H2 finger variants, including C4HC3- (RING-CH alias RINGv), C3H3C2-, C3H2C2D-, C3DHC3-, and C4HC2H-type modified RING-H2 fingers. The canonical RING-H2 finger has been defined as C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-H-X2-C-X(4-48)-C-X2-C, X is any amino acid and the number of X residues varies in different fingers. It binds two Zn ions in a unique "cross-brace" arrangement, which distinguishes it from tandem zinc fingers and other similar motifs. RING-H2 finger can be found in a group of diverse proteins with a variety of cellular functions, including oncogenesis, development, viral replication, signal transduction, the cell cycle and apoptosis. Many of them are ubiquitin-protein ligases (E3s) that serves as a scaffold for binding to ubiquitin-conjugating enzymes (E2s, also referred to as ubiquitin carrier proteins or UBCs) in close proximity to substrate proteins, which enables efficient transfer of ubiquitin from E2 to the substrates.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 1002231267 197 CPICFEyLFESTNDVSVLPCGHTIHVKCLREMEEHCQFACPLC 239
Cdd:cd16448     1 CVICLE-EFEEGDVVRLLPCGHVFHLACILRWLESGNNTCPLC 42

RING-finger-containing ubiquitin ligase [Posttranslational modification, protein turnover, chaperones];

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*...
gi 1002231267 196 DCPICFEYlFESTNDVSVLPCGHTIHVKCLREMEEHCQFACPLCSKSV 243
Cdd:COG5540   325 ECAICMSN-FIKNDRLRVLPCDHRFHVGCVDKWLLGYSNKCPVCRTAI 371