Fig. 7. Gastrin stimulates JNK activation through a CrkII-independent mechanism. CHO cells expressing the CCKBR stably transfected with dominant negative mutant of CrkII (CRK-) or the empty vector (CHO-CCKB) were stimulated for the times indicated with 10 nM gastrin. A and B, whole cell lysates were immunoblotted with an anti-CrkII (A) or anti-phospho-Thr183 and -Tyr185 JNK antibody (B). C, after IP with an anti-JNK1 antibody, JNK activity using GST-c-Jun-(179) as an exogenous substrate was assayed as described in "Materials and Methods." Comparable amounts of proteins were detected in whole cell lysates or immunoprecipitates of all of the above-mentioned experiments (data not shown).