Flippases and vesicle-mediated protein transport.
The best-understood mechanisms for generating transport vesicles in the secretory and endocytic pathways involve the localized assembly of cytosolic coat proteins such as clathrin, coat protein complex (COP)I and COPII onto membranes. These coat proteins can deform membranes by themselves, but accessory proteins might help to generate the tight curvature needed to form a vesicle. Enzymes that pump phospholipid from one leaflet of the bilayer to the other (flippases) can deform membranes by creating an imbalance in the phospholipid number between the two leaflets. Recent studies describe a requirement for the yeast Drs2p family of P-type ATPases in both phospholipid translocation and protein transport in the secretory and endocytic pathways. This indicates that flippases work with coat proteins to form vesicles.
Graham
Todd R
TR
Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634, USA. trgraham@vanderbilt.edu
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002966:Clathrin / Q000378:metabolism; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D008954:Models, Biological; D049294:Phospholipid Transfer Proteins / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D022161:Transport Vesicles / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism*
D002966:Clathrin; C104014:DRS2 protein, S cerevisiae; D008565:Membrane Proteins; D049294:Phospholipid Transfer Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D000252:Calcium-Transporting ATPases