Selective inhibition of adaptor complex-mediated vesiculation.

A short while ago, we could only inhibit post-Golgi membrane traffic with crude, unselective tools, such as low temperature or high extracellular sucrose. Molecular dissection of vesiculation steps has revealed unexpected complexity in the coating machinery that has initiated a search for more specific inhibitors. We have learned that membrane vesiculation is driven by a tightly regulated multicomponent, membrane-associated protein machine held together by carefully specified interaction domains. An experimental advantage of such complex interacting machinery is that it is very susceptible to disruption by dominant negative inhibitors or by overexpression. As a result, we now have much more specific inhibitors of post-Golgi membrane traffic. Some, such as dynamin K44A, may be general inhibitors, whereas others can distinguish classes of endocytotic events (10), binding events that require clathrin from those that do not (42), or specific steps of endocytosis (62). Ligand-mediated uptake of EGF and numerous, but not all, GPCRs can be inhibited by overexpression of an ARF GTPase-activating protein that has no effect on transferrin uptake (67). We can look forward to increasingly powerful and selective inhibitors that should help us to navigate successfully the complex routes of post-Golgi membrane traffic.