1ygu
From Proteopedia
Crystal structure of the tandem phosphatase domains of RPTP CD45 with a pTyr peptide
Structural highlights
Disease[PTPRC_HUMAN] T-B+ severe combined immunodeficiency due to CD45 deficiency. The disease is caused by mutations affecting the gene represented in this entry. Disease susceptibility may be associated with variations affecting the gene represented in this entry. Function[PTPRC_HUMAN] Protein tyrosine-protein phosphatase required for T-cell activation through the antigen receptor. Acts as a positive regulator of T-cell coactivation upon binding to DPP4. The first PTPase domain has enzymatic activity, while the second one seems to affect the substrate specificity of the first one. Upon T-cell activation, recruits and dephosphorylates SKAP1 and FYN. Dephosphorylates LYN, and thereby modulates LYN activity (By similarity). [MT_POVMA] Plays a role in transformation by modulating the activities of cellular proteins involved in control of cell proliferation and by acting as a functional homolog of an activated tyrosine kinase-associated growth-factor receptor. Recruits upon association with host Ppp2/PP2A the Src tyrosine kinase components Src, Yes and Fyn, thereby activating their kinase activity. Activation of Shc1, Pclg1 and p85 mediate signal transduction pathways leading to cell cycle progression and cell division. MT plays also a role in regulation of early and late gene expression and in viral DNA replication.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCD45 is the prototypic member of transmembrane receptor-like protein tyrosine phosphatases (RPTPs) and has essential roles in immune functions. The cytoplasmic region of CD45, like many other RPTPs, contains two homologous protein tyrosine phosphatase domains, active domain 1 (D1) and catalytically impaired domain 2 (D2). Here, we report crystal structure of the cytoplasmic D1D2 segment of human CD45 in native and phosphotyrosyl peptide-bound forms. The tertiary structures of D1 and D2 are very similar, but doubly phosphorylated CD3zeta immunoreceptor tyrosine-based activation motif peptide binds only the D1 active site. The D2 "active site" deviates from the other active sites significantly to the extent that excludes any possibility of catalytic activity. The relative orientation of D1 and D2 is very similar to that observed in leukocyte common antigen-related protein with both active sites in an open conformation and is restrained through an extensive network of hydrophobic interactions, hydrogen bonds, and salt bridges. This crystal structure is incompatible with the wedge model previously suggested for CD45 regulation. Structural basis for the function and regulation of the receptor protein tyrosine phosphatase CD45.,Nam HJ, Poy F, Saito H, Frederick CA J Exp Med. 2005 Feb 7;201(3):441-52. Epub 2005 Jan 31. PMID:15684325[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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