Actin and myosin IIA interaction with WIP is independent of WASp. YTS/KIR2DL1 cells were transfected with FLAG-WIP or FLAG-WIPΔ460-503, which is a mutant protein lacking the WASp binding domain. Transfected cells were mixed with 721.221 cells and incubated for the indicated times at 37°C. Cell lysates were immunoprecipitated with anti-FLAG mAb. Immunoprecipitated proteins were immunoblotted with anti–myosin IIA, anti-FLAG, anti-WASp, or anti-actin antibodies. The molecular masses of the proteins according to their position relative to molecular mass markers are shown in parentheses. The absence of WASp does not affect recruitment of either actin or myosin IIA to the complex.