Figure 3.

USP10 interacts with Smad4 in vivo. (A) USP10 interacts with Smad4 in vivo. 293T cells cotransfected as indicated with expression plasmids encoding HA‐tagged Smad4 and nontagged USP10 cells were lysed, and lysates were incubated with anti‐HA affinity gel. Proteins retained on anti‐HA affinity gel were blotted with the indicated antibodies. (B) The catalytic activity of USP10 is not required for Smad4 binding. 293T cells were cotransfected with expression plasmids encoding Flag‐tagged Smad4 and nontagged USP10 (WT or C424A). Cell lysates were prepared for Co‐IP with anti‐Flag antibody, followed by western blotting as indicated. (C) Endogenous USP10 interacts with Smad4 in vivo. 293T cells were transfected as indicated with expression plasmids encoding Flag‐tagged Smad4. Cell lysates were immunoprecipitated with anti‐Flag antibody to examine the interaction of Flag‐tagged Smad4 and endogenous USP10. (D) Smad4 interacts with USP10 at endogenous levels. Cell lysates were immunoprecipitated with anti‐Smad4 antibody to examine the interaction of Smad4/USP10 at endogenous levels. The value of Co‐IP/IP ratio is about 15%.