Figure 6.

N-terminal deletion mutants can induce paxillin phosphorylation. (A) Cells transfected with empty RCAS (lanes 1 and 2) and cells expressing wild-type FAK (lanes 3 and 4), dl 1–361 (lanes 5 and 6), or dl 51–377 (lanes 7 and 8) were incubated overnight in the absence (lanes 1, 3, 5, and 7) or presence (lanes 2, 4, 6, and 8) of 50 μM sodium vanadate. The cells were lysed, and paxillin was immunoprecipitated. The immune complexes were analyzed by Western blotting using an anti-phosphotyrosine antibody (top) and a paxillin monoclonal antibody (bottom). The arrowheads denote the position of the 68-kDa marker. (B) Control transfected cells (lanes 1 and 2) and cells expressing wild-type FAK (lanes 3 and 4), dl 721–857 (lanes 5 and 6), FAK^454R (K454R; lanes 7 and 8), or FAK^564A (D564A; lanes 9 and 10) were incubated overnight in the absence (lanes 1, 3, 5, 7, and 9) or presence (lanes 2, 4, 6, 8, and 10) of 50 μM sodium vanadate. Cells were lysed, and paxillin was immunoprecipitated and analyzed as described in A.