Figure 2.

JAM-A regulates β1-integrin protein expression and Rap1 GTPase activity in breast cancer cells. (a) Western blot analysis of a panel of alpha- and beta-subunit integrins was conducted on MCF7 cell lines transfected with control short interfering RNA (siRNA) or JAM-A-siRNA. Assessment of actin expression was performed to control for protein loading. (b) Densitometry analysis of triplicate Western blot experiments showing relative protein expression of alpha- and beta-subunit integrins. Error bars refer to standard deviation of triplicate experiments. (c) β1-integrin Western blot analysis of equal total protein lysates (input) and JAM-A immunoprecipitates (IP:JAM-A) from MCF7 cells transfected with control siRNA or JAM-A-siRNA. (d) Western blot analysis of JAM-A, total Rap1, and active Rap1 protein expression in MCF7 cells transfected with control or JAM-A siRNA and in MCF7 cells treated with isotype control antibody or JAM-A inhibitory antibody. (e) Densitometric analysis of triplicate JAM experiments showing the ratio of active to total Rap1 after JAM-A knockdown or antagonism. Error bars refer to standard deviation of triplicate experiments. JAM-A, junctional adhesion molecule-A.