Figure 4.

Cysteines 2 and 12 of RGS4 are the likely sites of palmitate incorporation. Sf9 cells expressing wild type (WT), C2A-, C12A-, or C33A- RGS4-myc were labeled with [³H]palmitate. The labeled protein was immunoprecipitated from detergent extracts of membranes and subjected to SDS/PAGE and fluorography (Upper). Because C2A RGS4-myc was expressed at lower levels than wild type or the other cysteine substitution mutants, the amount of detergent extract immunoprecipitated for each sample was adjusted to produce equal amounts of RGS4 protein as indicated in the Coomassie blue-stained gel (Lower).