FIGURE 5:

CK2-dependent PAK1 phosphorylation is critical for growth of the prostate cancer PC3 cells. (A) Cell extracts of PC3 cells with (sh1) or without (NT) CK2α knockdown were subjected to Western blot analysis with anti-pPAK1^S144, anti-PAK1^S199, anti-PAK1, anti-CK2α, or anti-actin antibody. (B) PC3 cells with (sh1) or without (NT) CK2α knockdown were incubated for 1 d in the absence of serum and then cultured in the presence (+) or absence (−) of EGF (100 ng/ml) for 1 h, and total cell extracts were subjected to Western blot analysis with anti-pPAK1^S223, anti-PAK1^S144, anti-CK2α, or anti-actin antibody. (C) Western blot analysis of expression of PAK1 and PAK2 in PC3 cells with (sh1 and sh2) or without (NT) PAK1 or PAK2 knockdown (left) and MTT proliferation assay of the PC3 cells (right).