CIB interacts with and regulates FAK activity. (A) Immunoprecipitation of CIB from mock- and CIB-transfected CHO cell lysates. Western blot analysis with anti-FAK that shows CIB interacts with FAK. (B) Immunoprecipitate kinase assay using mock- and CIB-transfected CHO cell lysates. Although FAK expression levels are similar (WB: FAK), the amount of phosphotyrosine is up-regulated on CIB overexpression (WB: pY). FAK activity is also up-regulated on CIB cell overexpression (Autoradiogram). (C) Haptotactic transwell migration assay performed on fibronectin using mock-, CIB-, and FRNK-transfected CHO cells, as well as CIB + FRNK-cotransfected cells. FRNK inhibits CIB-induced CHO migration on fibronectin. Error bars indicate mean ± SEM of at least 3 independent experiments.