Signaling pathway to BCR-induced Mcl-1 expression.
(A, B) CD43- splenic B cells from Bim-/- mice were treated with anti-IgM F(ab’)2 (15μg/ml) for various times in the presence or absence of Syk kinase inhibitor R406 (4μM), Bruton’s tyrosine kinase inhibitor Ibrutinib (PCI-32765) (20nM), or TORC1 inhibitor rapamycin (50nM). Whole cell extracts were fractionated by SDS-PAGE and Mcl-1 protein was analyzed by immunoblotting. β-actin was used as a loading control to normalize between samples. (C, D) CD43- splenic B cells from BL6, BCAP-/- (C) or CD19-/- (D) mice were cultured for the indicated times with or without anti-IgM F(ab’)2 (15μg/ml). Whole cell extracts were prepared and assayed for Mcl-1 levels by Western blot analysis. β-actin was used as a loading control to normalize between samples. Representative gels from 3 independent experiments are shown for A and B and 2 independent experiments for C and D. Cell viability profile of BCAP-/- and CD19-/- B cells are shown in S4 Fig.
