phosphoacceptor receiver (REC) domain of type A Arabidopsis response regulators (ARRs) and similar proteins
Type-A response regulators of Arabidopsis (ARRs) are involved in cytokinin signaling, which involves a phosphorelay cascade by histidine kinase receptors (AHKs), histidine phosphotransfer proteins (AHPs) and downstream ARRs. Cytokinin is a plant hormone implicated in many growth and development processes including shoot organogenesis, leaf senescence, sink/source relationships, vascular development, lateral bud release, and photomorphogenic development. Type-A ARRs function downstream of and are regulated by type-B ARRs, which are a class of MYB-type transcription factors. As primary cytokinin response genes, type-A ARRs act as redundant negative feedback regulators of cytokinin signaling by inactivating the phosphorelay. ARRs are divided into two groups, type-A and -B, according to their sequence and domain structure. Type-A ARRs are similar in domain structure to CheY, in that they lack a typical output domain and only contain a stand-alone receiver (REC) domain. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.
Feature 1: metal binding site [ion binding site], 3 residue positions
Conserved feature residue pattern:[ED] [ED] [ED]
Evidence:
Comment:based on metal binding site of other family members
Comment:signal transduction in two-component systems is mediated by metal ion dependent phosphorelay reactions between protein histidine kinases and phosphoaccepting receiver domains in response regulator proteins
Comment:for many receivers, Mg2+ is the preferred metal ion, but other divalent ions such as Mn2+ are also used
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