FIG. 5.

The catalytic region of SHIP-1 is sufficient to mediate the inhibitory effect of Dok-3 on BCR-triggered cytokine production. Pools of stable A20 transfectants expressing Dok-3-SHIP-1 or N-Dok-3 were tested. (A) Expression levels. The expression levels of the chimeric proteins were ascertained by immunoblotting of equivalent quantities of cell proteins with anti-FLAG. (B) BCR-induced IL-2 secretion. Antigen receptor-triggered IL-2 secretion was tested as outlined for Fig. 1C. Assays were done in triplicate and average values with standard deviations are shown. (C) Responsiveness to PMA plus ionomycin. Cells were tested as detailed for Fig. 1E. Assays were done in triplicate, and average values with standard deviations are shown.