CIN85 promotes Syk ubiquitination and degradation in B cells. (A) Control BJAB cells, stable transformants expressing WT CIN85, and CIN85- knockdown BJAB cells were stimulated with 20 μg/mL F(ab′)2 goat anti–human IgM for the indicated time periods. Immunoprecipitates with anti-Syk mAb were separated on a 10% SDS-PAGE gel and analyzed by Western blotting with anti-ubiquitin or anti-Syk mAb. 5′'c, immunoprecipitation of the cell lysates at 5 minutes with isotype control. The molecular weight is indicated on the left side of the blots. (B) Control BJAB cells, stable transformants expressing WT CIN85, and CIN85-knockdown BJAB cells were stimulated with 20 μg/mL F(ab′)2 goat anti–human IgM for 5 minutes. Immunoprecipitates with anti-Syk mAb were separated on a 10% SDS-PAGE gel and analyzed by Western blotting with anti–phospho-Syk pAb or anti-Syk mAb.
