Figure 3. In vitro phosphorylation of hBest1 C-terminus by PKC.

A, incorporation of ³²P as a function of hBest1 C-terminus protein concentration. Reactions were incubated at 30°C for 30 min with 100 ng of PKC. Phosphorylation stoichiometry is estimated to be 0.32 pmol ³²P/pmol protein. B, absence of phosphorylation of the S358E mutant of the hBest1 C-terminus. Incorporation of ³²P by 5 μg of purified wild-type and S358E mutant fusion proteins was measured (n= 3).