The intracellular dynamic of protein palmitoylation

Salaun, Christine; Greaves, Jennifer; Chamberlain, Luke H.

Immediately after microinjection, farnesylated N-Ras displayed a dispersed localization, which is consistent with its presence in the cytosol and transient association with intracellular membranes . However, a rapid enrichment of the Cy3-labeled construct became apparent at the Golgi region (t/2 14 s) with plasma membrane staining visible at later time points. The simplest interpretation of these observations is that palmitoylation of the farnesylated N-Ras occurs at the Golgi, promoting early accumulation at this compartment, and is followed by anterograde transport to the plasma membrane. This notion agrees well with previous analyses of Ras protein cycling (Goodwin et al., 2005; Rocks et al., 2005) . Nevertheless, it should be noted that palmitoylation of the microinjected semisynthetic Ras protein was not directly assayed in this study. Although technically challenging, it will therefore be of major interest in follow-up studies to perform correlative measurements of palmitoylation and intracellular localization of microinjected Ras. In addition, a recently published study reported that palmitoylated Ras proteins traffic from Golgi to recycling endosomes en route to the plasma membrane (Misaki et al., 2010) .