1ygr | pdb_00001ygr
Crystal structure of the tandem phosphatase domain of RPTP CD45
Structural highlights
Disease[CD45_HUMAN] Defects in PTPRC are a cause of severe combined immunodeficiency autosomal recessive T-cell-negative/B-cell-positive/NK-cell-positive (T(-)B(+)NK(+) SCID) [MIM:608971]. A form of severe combined immunodeficiency (SCID), a genetically and clinically heterogeneous group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity, leukopenia, and low or absent antibody levels. Patients present in infancy recurrent, persistent infections by opportunistic organisms. The common characteristic of all types of SCID is absence of T-cell-mediated cellular immunity due to a defect in T-cell development.[1] Genetic variations in PTPRC are involved in multiple sclerosis susceptibility (MS) [MIM:126200]. MS is a neurodegenerative disorder characterized by the gradual accumulation of focal plaques of demyelination particularly in the periventricular areas of the brain. Peripheral nerves are not affected. Onset usually in third or fourth decade with intermittent progression over an extended period. The cause is still uncertain.[2] [CD3Z_HUMAN] Defects in CD247 are the cause of immunodeficiency due to defect in CD3-zeta (CD3ZID) [MIM:610163]. An immunological deficiency characterized by T-cells impaired immune response to alloantigens, tetanus toxoid and mitogens.[3] Function[CD45_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).[4] [5] [CD3Z_HUMAN] Probable role in assembly and expression of the TCR complex as well as signal transduction upon antigen triggering. 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[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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