Biogenesis of transport intermediates in the endocytic pathway

Evidence is accumulating that membrane traffic between organelles can be ac hieved by different types of intermediates. Small (< 100 nm) and short-live d vesicles mediate transport from the plasma membrane or the trans-Golgi ne twork to endosomes, and formation of these vesicles depends on specific ada pter complexes, In contrast, transport from early to late endosomes is achi eved by relatively large (similar to 0.5 mu m), long-lived and multivesicul ar intermediates, and their biogenesis depends on endosomal COP-I proteins. Here, we review recent work on the formation of these different transport intermediates, and we discuss, in particular, coat proteins, sorting signal s contained in cargo molecules and the emerging role of lipid in vesicle bi ogenesis, (C) 1999 Federation of European Biochemical Societies.