FIGURE 7.

Both wild-type and kinase-inactive CK2α interact with the RAF-MEK-ERK scaffold protein KSR1. Endogenous KSR1 was immunoprecipitated (IP) from A375 cells expressing the GFP control or FLAG-tagged CK2α(WT) or kinase-inactive CK2α(K68M). Whole cell lysates and immunoprecipitates were then blotted for the presence of FLAG-CK2α and reprobed for KSR1 to ensure that equal amounts of KSR1 were immunoprecipitated. *IgG bands are from immunoprecipitation step. GFP served as a negative control to rule out nonspecific co-immunoprecipitation of the ectopic CK2α proteins (n = 2).