Fig. 5. Kette and Sra-1 stabilize each other. (A-C) Top row, expression of Kette (green) in S2R+ cells; bottom row, F-actin was detected using phalloidin (red). (A) Wild-type S2R+ cells grown on an adhesive substrate. (B) Kette expression in S2R+ cells can be suppressed by treatment with double-stranded kette RNA (RNAi). Retraction fibers and clumps of F-actin are found within the cells (arrowheads). (C) When sra-1 function is inhibited by sra-1 RNAi, Kette protein expression cannot be detected after 2 days of RNAi treatment. In addition, a F-actin phenotype develops (compare B with C). (D) Western blot analysis showing mutual protein stabilization of Kette and Sra-1. sra-1 RNAi affects Sra-1 and Kette expression and, conversely, kette RNAi efficiently reduces Kette and Sra-1 protein expression.