Syk expression and activity in NHL-like murine tumor B cells. Representative Western blot of naive and anti-IgM stimulated (5 minutes) wild-type B cells from spleen compared with 2 separate tumor spleens each from Eμ-MYC, Eμ-MYC/BCR^HEL, and Eμ-MYC/BCR^HEL/sHEL mice. Cells were lysed with 1% Triton X-100 in the presence of phosphatase and protease inhibitors, and blotted for anti–phospho-Syk (human Y525/526) (middle panel), stripped and reprobed for anti-Syk (top panel), and then stripped a second time and probed for anti–β-actin loading control (bottom panel).