4a4b: Difference between revisions
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{{STRUCTURE_4a4b| PDB=4a4b | SCENE= }} | {{STRUCTURE_4a4b| PDB=4a4b | SCENE= }} | ||
===Structure of modified phosphoTyr371-c-Cbl-UbcH5B-ZAP-70 complex=== | ===Structure of modified phosphoTyr371-c-Cbl-UbcH5B-ZAP-70 complex=== | ||
{{ABSTRACT_PUBMED_22266821}} | |||
==Disease== | |||
[[http://www.uniprot.org/uniprot/CBL_HUMAN CBL_HUMAN]] Defects in CBL are the cause of Noonan syndrome-like disorder with or without juvenile myelomonocytic leukemia (NSLL) [MIM:[http://omim.org/entry/613563 613563]]. A syndrome characterized by a phenotype reminiscent of Noonan syndrome. Clinical features are highly variable, including facial dysmorphism, short neck, developmental delay, hyperextensible joints and thorax abnormalities with widely spaced nipples. The facial features consist of triangular face with hypertelorism, large low-set ears, ptosis, and flat nasal bridge. Some patients manifest cardiac defects.<ref>PMID:20619386</ref> [[http://www.uniprot.org/uniprot/ZAP70_HUMAN ZAP70_HUMAN]] Defects in ZAP70 are the cause of selective T-cell defect (STCD) [MIM:[http://omim.org/entry/269840 269840]]. A form of severe combined immunodeficiency characterized by a selective absence of CD8+ T cells.<ref>PMID:8124727</ref><ref>PMID:8202713</ref><ref>PMID:11412303</ref><ref>PMID:11123350</ref><ref>PMID:18509675</ref> | |||
< | ==Function== | ||
[[http://www.uniprot.org/uniprot/CBL_HUMAN CBL_HUMAN]] Adapter protein that functions as a negative regulator of many signaling pathways that are triggered by activation of cell surface receptors. Acts as an E3 ubiquitin-protein ligase, which accepts ubiquitin from specific E2 ubiquitin-conjugating enzymes, and then transfers it to substrates promoting their degradation by the proteasome. Recognizes activated receptor tyrosine kinases, including KIT, FLT1, FGFR1, FGFR2, PDGFRA, PDGFRB, EGFR, CSF1R, EPHA8 and KDR and terminates signaling. Recognizes membrane-bound HCK and other kinases of the SRC family and mediates their ubiquitination and degradation. Participates in signal transduction in hematopoietic cells. Plays an important role in the regulation of osteoblast differentiation and apoptosis. Essential for osteoclastic bone resorption. The Tyr-731 phosphorylated form induces the activation and recruitment of phosphatidylinositol 3-kinase to the cell membrane in a signaling pathway that is critical for osteoclast function.<ref>PMID:10514377</ref><ref>PMID:11896602</ref><ref>PMID:14739300</ref><ref>PMID:15190072</ref><ref>PMID:17509076</ref><ref>PMID:18374639</ref><ref>PMID:19689429</ref><ref>PMID:21596750</ref> [[http://www.uniprot.org/uniprot/UB2D2_HUMAN UB2D2_HUMAN]] Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro catalyzes 'Lys-48'-linked polyubiquitination. Mediates the selective degradation of short-lived and abnormal proteins. Functions in the E6/E6-AP-induced ubiquitination of p53/TP53. Mediates ubiquitination of PEX5 and autoubiquitination of STUB1 and TRAF6. Involved in the signal-induced conjugation and subsequent degradation of NFKBIA, FBXW2-mediated GCM1 ubiquitination and degradation, MDM2-dependent degradation of p53/TP53 and the activation of MAVS in the mitochondria by DDX58/RIG-I in response to viral infection. Essential for viral activation of IRF3.<ref>PMID:10329681</ref><ref>PMID:15280377</ref><ref>PMID:18042044</ref><ref>PMID:18703417</ref><ref>PMID:18359941</ref><ref>PMID:19854139</ref><ref>PMID:20403326</ref><ref>PMID:20061386</ref> [[http://www.uniprot.org/uniprot/ZAP70_HUMAN ZAP70_HUMAN]] Tyrosine kinase that plays an essential role in regulation of the adaptive immune response. Regulates motility, adhesion and cytokine expression of mature T-cells, as well as thymocyte development. Contributes also to the development and activation of primary B-lymphocytes. When antigen presenting cells (APC) activate T-cell receptor (TCR), a serie of phosphorylations lead to the recruitment of ZAP70 to the doubly phosphorylated TCR component CD247/CD3Z through ITAM motif at the plasma membrane. This recruitment serves to localization to the stimulated TCR and to relieve its autoinhibited conformation. Release of ZAP70 active conformation is further stabilized by phosphorylation mediated by LCK. Subsequently, ZAP70 phosphorylates at least 2 essential adapter proteins: LAT and LCP2. In turn, a large number of signaling molecules are recruited and ultimately lead to lymphokine production, T-cell proliferation and differentiation. Furthermore, ZAP70 controls cytoskeleton modifications, adhesion and mobility of T-lymphocytes, thus ensuring correct delivery of effectors to the APC. ZAP70 is also required for TCR-CD247/CD3Z internalization and degradation through interaction with the E3 ubiquitin-protein ligase CBL and adapter proteins SLA and SLA2. Thus, ZAP70 regulates both T-cell activation switch on and switch off by modulating TCR expression at the T-cell surface. During thymocyte development, ZAP70 promotes survival and cell-cycle progression of developing thymocytes before positive selection (when cells are still CD4/CD8 double negative). Additionally, ZAP70-dependent signaling pathway may also contribute to primary B-cells formation and activation through B-cell receptor (BCR).<ref>PMID:1423621</ref><ref>PMID:8124727</ref><ref>PMID:8702662</ref><ref>PMID:9489702</ref><ref>PMID:11353765</ref> | |||
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==About this Structure== | ==About this Structure== | ||
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==Reference== | ==Reference== | ||
<ref group="xtra">PMID:022266821</ref><references group="xtra"/> | <ref group="xtra">PMID:022266821</ref><references group="xtra"/><references/> | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Non-specific protein-tyrosine kinase]] | [[Category: Non-specific protein-tyrosine kinase]] | ||