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Nat Immunol. 2001 Oct;2(10):897-8.
Direct inhibition of Bruton's tyrosine kinase by IBtk, a Btk-binding protein.
Department of Clinical and Experimental Medicine, Medical School, University of Catanzaro, 88100 Catanzaro, Italy.
Bruton's tyrosine kinase (Btk) is required for human and mouse B cell development. Btk deficiency causes X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency in mice. Unlike Src proteins, Btk lacks a negative regulatory domain at the COOH terminus and may rely on cytoplasmic Btk-binding proteins to regulates its kinase activity by trans-inhibitor mechanisms. Consistent with this possibility, IBtk, which we identified as an inhibitor of Btk, bound to the PH domain of Btk. IBtk downregulated Btk kinase activity, Btk-mediated calcium mobilization and nuclear factor-kappaB-driven transcription. These results define a potential mechanism for the regulation of Btk function in B cells.
PMID: 11577348 [PubMed - indexed for MEDLINE]