In contrast to other static lipid modifications, the versatility of palmitoylation as a membrane interaction and protein sorting module is greatly enhanced by its reversibility. It has long been appreciated that the palmitoylation of many (but not all) proteins is dynamic (Magee et al., 1987) and can be modulated in response to cell stimulation (Degtyarev et al., 1993; Mumby et al., 1994; Wedegaertner and Bourne, 1994) . Although palmitoylation dynamics of transmembrane proteins can impact sorting to distinct membrane compartments, depalmitoylation of soluble proteins can also mediate membrane release and cytosolic diffusion. Thus, the rapid palmitoylation and depalmitoylation dynamics of many proteins add an extra level of complexity to the effects of this posttranslational modification on protein sorting.