FIGURE 1.

RSPH3 binds to ERK1/2 and other cascade components. A, endogenous ERK1/2 were immunoprecipitated from HEK293 cell lysates expressing 3xFLAG-RSPH3 or empty vector (negative control) and immunoblotted (IB) with the anti-FLAG antibody. Lanes labeled whole cell lysate (WCL) contain 10% of the input for immunoprecipitation. Immunoprecipitation with normal rabbit IgG was used as a negative control. B, yeast were co-transformed with plasmids containing mouse RSP3 and ERK2, MEK1R4F, a co-expression plasmid containing ERK2 plus MEK1R4F, or empty vector as a control. C, endogenous ERK1/2, MEK1, and Rsk (top) or Rsk and OSR1 (bottom) were immunoprecipitated from cells transfected with 3xFLAG-RSPH3. Precipitates were immunoblotted with anti-FLAG antibodies. Normal IgG was immunoprecipitated as control. The whole cell lysate lane contains 5% of the input for immunoprecipitation. Experiments in A–C were repeated 10, 2, and 3 times.