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(Redirected from Zap-70)
'ZAP-70' is an abbrevation for 'Zeta-chain-associated protein kinase 70' (70 is the molecular weight in kDa). The protein is a member in the protein-tyrosine kinase family. ZAP-70 is normally expressed in T cells and natural killer cells and has a critical role in the initiation of T-cell signaling. ZAP-70 in B cells is used as a prognostic marker in identifying different forms of chronic lymphocytic leukemia (CLL).
T lymphocytes are activated by engagement of the T cell receptor with processed antigen fragments presented by professional antigen presenting cells (e.g. macrophages, dendritic cells and B cells). Upon this activation, the tyrosine kinase Lck becomes activated and phosphorylates the intracellular portions of the CD3 complex (called ITAMs). The most important member of the CD3 family is CD3-zeta to which ZAP-70 binds (hence the abbreviation). The tandem SH2-domains of ZAP-70 are engaged by the doubly phosphorylated ITAMs of CD3-zeta, which positions ZAP-70 to phosphorylate the transmembrane protein LAT (Linker of Activated T cells). Phosphorylated LAT in turn serves as a docking site to which a number of signaling proteins bind. The final outcome of T cell activation is the transcription of several gene products which allow the T cells to differentiate, proliferate and secrete a number of cytokines.
★ Lck
★ Syk
★ ZAP-70: a 70 kd protein-tyrosine kinase that associates with the TCR zeta chain, Chan AC, Iwashima M, Turck CW, Weiss A, , , Cell, 1992
★ Structural Basis for the Inhibition of Tyrosine Kinase Activity of ZAP-70, Deindl S, Kadlecek TA, Brdicka T, Cao X, Weiss A, Kuriyan J, , , Cell, 2007
★
'ZAP-70' is an abbrevation for 'Zeta-chain-associated protein kinase 70' (70 is the molecular weight in kDa). The protein is a member in the protein-tyrosine kinase family. ZAP-70 is normally expressed in T cells and natural killer cells and has a critical role in the initiation of T-cell signaling. ZAP-70 in B cells is used as a prognostic marker in identifying different forms of chronic lymphocytic leukemia (CLL).
T lymphocytes are activated by engagement of the T cell receptor with processed antigen fragments presented by professional antigen presenting cells (e.g. macrophages, dendritic cells and B cells). Upon this activation, the tyrosine kinase Lck becomes activated and phosphorylates the intracellular portions of the CD3 complex (called ITAMs). The most important member of the CD3 family is CD3-zeta to which ZAP-70 binds (hence the abbreviation). The tandem SH2-domains of ZAP-70 are engaged by the doubly phosphorylated ITAMs of CD3-zeta, which positions ZAP-70 to phosphorylate the transmembrane protein LAT (Linker of Activated T cells). Phosphorylated LAT in turn serves as a docking site to which a number of signaling proteins bind. The final outcome of T cell activation is the transcription of several gene products which allow the T cells to differentiate, proliferate and secrete a number of cytokines.
| Contents |
| See also |
| References |
| External links |
See also
★ Lck
★ Syk
References
★ ZAP-70: a 70 kd protein-tyrosine kinase that associates with the TCR zeta chain, Chan AC, Iwashima M, Turck CW, Weiss A, , , Cell, 1992
★ Structural Basis for the Inhibition of Tyrosine Kinase Activity of ZAP-70, Deindl S, Kadlecek TA, Brdicka T, Cao X, Weiss A, Kuriyan J, , , Cell, 2007
External links
★
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