Pulse–chase analysis of wild-type and mutant Src proteins.
Src−/− MEFs were transfected with pLNCX vector
expressing c-Src, or the following Src mutants: Y527F, E378G, Y416F, or
K295R. Forty eight hours posttransfection, cells were pulse-labeled
with 100 μCi 35S Met/Cys for 45 min. Plates were
incubated in “chase” media with 100-fold excess methionine and
then harvested at the indicated times. Lysates were immunoprecipitated
by using mAb 327 and separated by SDS/PAGE. Gels were quantitated
with a PhosphorImager, and each time point was normalized to the 0-hr
time point.