Endocytosis and signaling cascades: a close encounter

Internalization of receptors and other cell surface components is well know n to occur via clathrin-mediated endocytosis, although other less well char acterized pathways are also involved. Internalized receptors are then deliv ered to early endosomes, where they are sorted to be recycled back to the p lasma membrane for reutilization or transported to late endosomes/lysosomes for degradation. Endocytosis has long been considered as a constitutive, h ousekeeping function of animal cells that occurs independently of the cellu lar environment in contrast to regulated secretion. Here, we a ill discuss recent studies that are uncovering the existence of cross-talk between sign aling molecules and components of the transport machinery, indicating that endocytosis can be modulated by signaling pathways. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B,V, All righ ts reserved.