Schip1 localizes to cell lamellipodia and associates with the cortical actin cytoskeleton.

<p><b>(A)</b> Both endogenous (arrowheads, upper panel) and ectopic (arrowheads, lower panel) Schip1 localize to lamellipodia in cultured human podocytes. <b>(B)</b> To test Schip1 association to actin-rich lamellipodia regions, transiently transfected human podocytes were treated with the standard procedure (fixation and Triton X-100 permeabilization, upper panel), or incubated with saponin prior to fixation and staining for MycSchip1 (lower panel). Peripheral Schip1 expression is partially retained after saponin treatment, indicating association of the protein with detergent-insoluble cytoskeletal/plasma membrane structures. The same was not observed in control cells transfected with Stx8 (syntaxin 8). <b>(C)</b> Schip1 colocalizes with cortical F-actin in the podocyte lamellipodia. Both the Z- and XY-scanning indicate considerable signal overlap between Schip1 and F-actin along the plasma membrane in cells presenting well-developed lamellipodia. <b>(D)</b> Treatment with latrunculin A results in the dissolution of actin fibers in both control and Schip1-transfected podocytes. However, Schip1 signal remains associated with disturbed F-actin positive residues. In contrast, treatment with cytochalasin D results mostly in preservation of the cortical actin in Schip1 transfected podocytes.