Erk1 and Erk2 are not constitutively phosphorylated in MIHCs expressing D816V c-Kit.

Cells were incubated in the presence or absence of huSCF for 10 minutes and lysed. Equivalent amounts of protein from the clarified lysates were immunoprecipitated (IP) with antisera specific for Erk1 or Erk2 (panels A and B, respectively) or with a matched control antibody, indicated by C. Immunoprecipitates were washed, and proteins were resolved with SDS-PAGE, transferred to Immobilon, and immunoblotted (IB) with antisera specific for phosphotyrosine (A and B, upper panels). Proteins were visualized with ECL. Blots were then stripped and reprobed with antisera specific for Erk1 (A, lower panel) or Erk2 (B, lower panel).