TY - JOUR
T1 - Cbl-b positively regulates Btk-mediated activation of phospholipase C-γ2 in B cells
AU - Yasuda, Tomoharu
AU - Tezuka, Tohru
AU - Maeda, Akito
AU - Inazu, Tetsuya
AU - Yamanashi, Yuji
AU - Gu, Hua
AU - Kurosaki, Tomohiro
AU - Yamamoto, Tadashi
PY - 2002/7/1
Y1 - 2002/7/1
N2 - 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)-γ2 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-γ2 and helped the association of PLC-γ2 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 NH2-terminal tyrosine kinase-binding domain and COOH-terminal half region of Cbl-b were essential for its association with PLC-γ2 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-γ2 complex formation.
AB - 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)-γ2 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-γ2 and helped the association of PLC-γ2 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 NH2-terminal tyrosine kinase-binding domain and COOH-terminal half region of Cbl-b were essential for its association with PLC-γ2 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-γ2 complex formation.
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U2 - 10.1084/jem.20020068
DO - 10.1084/jem.20020068
M3 - Article
C2 - 12093870
AN - SCOPUS:0036645535
SN - 0022-1007
VL - 196
SP - 51
EP - 63
JO - Journal of Experimental Medicine
JF - Journal of Experimental Medicine
IS - 1
ER -