FIG. 4.

The pp60^c-src complexed with the catalytically inactive C subunit mutants, D85N and R89A, is activated similarly to pp60^c-src complexed with wt C subunit. In vitro kinase assays were performed on anti-epitope tag immunoprecipitates prepared from cell lines expressing the control vector (GREonly) or epitope-tagged wt (wt-36) or mutant C subunits (see Fig. 2 for nomenclature). After incubation of the immunoprecipitates with [γ-³²P]ATP, proteins were separated by SDS-PAGE and phosphoproteins were visualized by autoradiography. The positions of the 43- and 68-kDa markers, pp60^c-src (c-src), the 85-kDa subunit of PI 3-kinase (PI3K) and MT (PYMT) are indicated. The data shown are representative of results obtained from two independent experiments.