Figure 4.

(A) TOB1 regulates cyclin D1 expression. Protein lysates were prepared from A549, A549-siRNA, NCI-H1975 and NCI-H1975-siRNA cells. (B) TOB1 forms protein-protein complex with cyclin D1 in A549 and NCI-H1975 cells. Whole cell lysate (1 mg) was immunoprecipitated with anti-TOB antibodies. The immunoprecipitated proteins were subsequently separated by SDS-PAGE, followed by immunoblotting with anti-cyclin D1 antibody, and then reprobing with TOB1 antibodies. All the experiments were performed independently at least three times.