The BioGRID | PUBLICATION VIEW

	J. Exp. Med. Jul (2002); 196(1):51-63
Cbl-b positively regulates Btk-mediated activation of phospholipase C-gamma2 in B cells.
Yasuda T, Tezuka T, Maeda A, Inazu T, Yamanashi Y, Gu H, Kurosaki T, Yamamoto T
Department of Oncology, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan.
Abstract: Genetic studies have revealed that Cbl-b plays a negative role in the antigen receptor-mediated proliferation of lymphocytes. However, we show that Cbl-b-deficient DT40 B cells display reduced phospholipase C (PLC)-gamma2 activation and Ca2+ mobilization upon B cell receptor (BCR) stimulation. In addition, the overexpression of Cbl-b in WEHI-231 mouse B cells resulted in the augmentation of BCR-induced Ca2+ mobilization. Cbl-b interacted with PLC-gamma2 and helped the association of PLC-gamma2 with Bruton's tyrosine kinase (Btk), as well as B cell linker protein (BLNK). Cbl-b was indispensable for Btk-dependent sustained increase in intracellular Ca2+. Both NH(2)-terminal tyrosine kinase-binding domain and COOH-terminal half region of Cbl-b were essential for its association with PLC-gamma2 and the regulation of Ca2+ mobilization. These results demonstrate that Cbl-b positively regulates BCR-mediated Ca2+ signaling, most likely by influencing the Btk/BLNK/PLC-gamma2 complex formation.
[PUBMED: 12093870]