Fig. 3.

IQGAP1 regulates cell proliferation in fibroblast NIH3T3 cells. (A) Lack of contact inhibition was measured over 6 days as the saturation density of stable cell lines growing in high-serum (10%) and presented as the means ± s.e.m. for n=4 (*P≤0.001). (B) Upper panel, proliferation rate in low serum (1%) was determined as saturation density over 6 days and presented as mean ± s.e.m. for n=4 experiments. Lower panel, photomicrographs of the cells on day 6. (C) Upper panel, growth in soft agar to measure anchorage-independent growth was determined as the number of foci ≥50 μm in diameter. Means ± s.e.m. for n=3 experiments are shown for four clones done in duplicate (*P<0.001). Lower panel, photomicrographs of the cells on day 10. (D) Endogenous IQGAP1 is required for transformation. Growth in low-serum medium for control (V) and IQGAP1-C cells untreated as positive control, or treated with scrambled (S) or two IQGAP1 siRNAs (R) that reduced the endogenous level by ∼90% as shown on the blot. Actin was detected as a loading control. P values indicate significant difference between highest and lowest values.