Synaptopodin knockdown does not affect RhoA. (A) Myosin IIA decorates apical and basal stress fibers in developing MDCK monolayer. Scale bar is 2 μm. (B) Myosin IIA colocalizes with myosin IIB at the contractomere in mature monolayer. Contractomeres are circled. Scale bar is 5 μm. (C) Synaptopodin knockdown does not affect RhoA activity in MDCK cells as assessed by Rhotekin pull-down and RhoA Western blot (see Materials and methods). (D) Western blots showing decreased ArgBP1/SORBS2 and phospho-myosin light chain levels in synaptopodin knockdown cells whereas RhoA and MRIP levels were unaffected. Markers are 100, 75, 50, and 25 kD.