Mutational analysis of the SH2-kinase linker region of Bruton's tyrosine kinase defines alternative modes of regulation for cytoplasmic tyrosine kinase families
| Autor: | Matthew I. Wahl, Shuling Guo, Owen N. Witte |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Immunology
Mutation Missense Mice Transgenic SH2 domain Lymphocyte Activation Receptor tyrosine kinase SH3 domain Cell Line src Homology Domains chemistry.chemical_compound Mice immune system diseases hemic and lymphatic diseases Agammaglobulinaemia Tyrosine Kinase Immunology and Allergy Bruton's tyrosine kinase Animals Calcium Signaling Kinase activity B-Lymphocytes biology Chemistry Tyrosine phosphorylation General Medicine Protein-Tyrosine Kinases Cell biology Amino Acid Substitution biology.protein Cancer research Tyrosine kinase Proto-oncogene tyrosine-protein kinase Src |
| Zdroj: | International immunology. 18(1) |
| ISSN: | 0953-8178 |
| Popis: | Bruton's tyrosine kinase (Btk) plays critical roles in B cell development and activation. Mutations of Btk cause X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency in mice. An Src homology domain 2-kinase linker region exists in all Src, Abl, ZAP70/Syk and Btk/Tec non-receptor tyrosine kinase families. Missense mutations in the Btk linker region can cause XLA, supporting an essential role for this protein segment. We investigated the regulatory role of the linker region in Btk function by mutational analysis. XLA-causing mutations L369F and R372G abolished Btk-mediated calcium response without affecting Btk protein stability and kinase activity significantly. Although mutation of a well-conserved tryptophan (W260A) in the linker region of the Src family kinase Hck has been shown to cause a hyperactive kinase, an analogous mutation in Btk (W395A) dramatically decreased Btk kinase activity. Tyrosine phosphorylation in the linker region was previously shown to regulate the function of Abl and ZAP70/Syk kinases. Even though tyrosine phosphorylation was detected on tyrosine 375 in the Btk linker region, no significant alteration was observed in Btk-signaling activity and biological function when this tyrosine was mutated in DT-40 cells or in Y375F knock-in mice. Our data and previous studies suggest that each cytoplasmic tyrosine kinase family has evolved a unique strategy to utilize the linker region to regulate the function of the enzyme. |
| Databáze: | OpenAIRE |
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