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Figure S3. Csk mitogenic activity does not require PAG in PDGF-stimulated cells. (A and B) PDGF induces Csk membrane translocation in a PAG-independent manner. An example (A) and statistical analysis (B) of PDGF-induced Csk membrane translocation assessed by immunostaining in NIH 3T3 quiescent cells treated, or not, with 1 µM SU6656 and stimulated, or not, with PDGF for 10 min. Down-regulation of PAG does not influence Csk translocation. (C) Csk can inhibit mitogenesis in cells with reduced PAG. NIH 3T3 cells expressing the indicated shRNAs were transfected, or not, with Csk, serum starved for 30 h, and then stimulated, or not, with PDGF in the presence of BrdU. Cells were then fixed and processed for immunofluorescence. The percentage of cells that incorporated BrdU was calculated as described in Material and methods. Results are expressed as the mean ± SD of six independent experiments.