IGF-I induces tyrosine phosphorylation of FAK in MM cells. MM cells starved for 12 hours were not stimulated or stimulated with varying concentrations of IGF-I (5 ng/mL to 200 ng/mL; A) for 10 minutes or with 100 ng/mL for times indicated (B). Cell lysates were subjected to SDS-PAGE (A) or immunoprecipitated with anti-FAK and subjected to SDS-PAGE (B), transferred to membranes, and blotted with indicated antibodies. Membranes in panel A were stripped and reprobed with anti-FAK as controls for loading. Control blot is shown only for H929, but comparable results were observed with all lines.