Effects of SOCS3-KIR mutant on PYK2 expression, Tyr402 and ERK1/2 activations and migration of A549 cells. (a) Down-regulations of PYK2 expression, Tyr402 and ERK1/2 phosphorylations by SOCS3-KIR mutant. A549 cells were transfected with either vector or the SOCS3-KIR mutant for 48 h, and cell lysates were subjected to western blot using the indicated antibodies. Cells pretreated with β-lactacystin showed that PYK2 expression, Tyr402 and ERK1/2 phosphorylations were restored to some extent. (b) PYK2 mRNA levels were unaffected regardless of transfection or not. The amplified PYK2 products were 629 bp in length. β-actin amplification demonstrated the consistency of PT-PCR. (c) Cell migration inhibited by the SOCS3-KIR mutant was statistically significant, and β-lactacystin pretreatment restored cell migration to some degree. The values are means of three replicates.