BCAP tyrosine phosphorylation in DT40 cells deficient in Lyn, Syk, or Btk.

Wild-type and its derived mutant DT40 cells expressing mouse CD19 were stimulated with CD19 and subsequently subjected to the following analyses. (A,B, left panels) Immunoprecipitation was performed with anti-BCAP Abs. The blots were stained with 4G10 mAb (upper panels) and anti-BCAP Abs (lower panels). Expression of wild-type (wt) Fyn or kinase-negative (kn) Fyn is shown by Western blot analysis using anti-Fyn Abs (B, right panel). (C) CD19-induced Akt activation in Lyn-deficient DT40 B cells.