D816V c-Kit is constitutively associated with higher levels of PI3K activity than wild-type c-Kit.

Indicated 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 with antisera specific for c-Kit and divided in half. One portion of the immunoprecipitate was used to assess c-Kit–associated PI3K activity (shown in panel A) as described in “Materials and methods.” The other portion of the c-Kit immunoprecipitate was resolved with SDS-PAGE, transferred to Immobilon, and immunoblotted (IB) with antisera specific for c-Kit (shown in panel B).