Figure 6.

CD-MPR palmitoylation upon wortmannin treatment in vivo. (A) Mouse L cells stably expressing MPR wt and MPR-FFW-YLL-A were pretreated with 1 μM wortmannin or 0.1% DMSO for 45 min and then labeled with [³H]palmitate for 90 min in the presence of 1 μM wortmannin (repeatedly added after every 45 min) or 0.1% DMSO. The cells were then chilled on ice and lysed. CD-MPR was immunoprecipitated and subjected to SDS-PAGE. [³H]Palmitate incorporation into CD-MPR was visualized by autoradiography. (B) Level of CD-MPR expression. Ten percent of the immunoprecipitated sample was subjected to SDS-PAGE and Western blotting (WB) with 22D4 mAb against CD-MPR. (C) Quantitation of [³H]palmitate incorporation into CD-MPR wt and FFW-YLL-A. The fluorography and the Western blot shown in A and B, respectively, and those from additional experiments were quantitated by densitometric scanning. In each experiment, the values obtained for the [³H]palmitate incorporation were corrected for the CD-MPR expression levels. The value obtained with the DMSO-treated CD-MPR wt was set to 1. The values are expressed as mean ± S.D. from three separate experiments.