Fig. 1. Effects of IL-3 and PMA on paxillin phosphorylation. Baf3 cells were deprived of IL-3 for 6 hours or grown on 10 ng/ml IL-3, and aliquots were treated 30 minutes with 4 µM cytochalasin D, 1 µM GF109203X, with 100 nM PMA alone or with 1 µM GF109203X and 100 nM PMA. Paxillin was immunoprecipitated (IP:Paxillin) and analyzed on western blot with a mixture of anti-phosphotyrosine antibodies 4G10 and PY20 (IB:PY) or with anti-paxillin (IB:Paxillin) antibody.