Clathrin-independent endocytosis: a unique platform for cell signaling and PM remodeling.
There is increasing interest in endocytosis that occurs independently of clathrin coats and the fates of membrane proteins internalized by this mechanism. The appearance of clathrin-independent endocytic and membrane recycling pathways seems to vary with different cell types and cargo molecules. In this review we focus on studies that have been performed using HeLa and COS cells as model systems for understanding this membrane trafficking system. These endosomal membranes contain signaling molecules including H-Ras, Rac1, Arf6 and Rab proteins, and a lipid environment rich in cholesterol and PIP(2) providing a unique platform for cell signaling. Furthermore, activation of some of these signaling molecules (H-Ras, Rac and Arf6) can switch the constitutive form of clathrin-independent endocytosis into a stimulated one, associated with PM ruffling and macropinocytosis.
Donaldson
Julie G
JG
Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA. jdonalds@helix.nih.gov
Porat-Shliom
Natalie
N
Cohen
Lee Ann
LA
D000818:Animals; D001692:Biological Transport; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism*; D002522:Chlorocebus aethiops; D002966:Clathrin / Q000378:metabolism; D004705:Endocytosis; D006367:HeLa Cells; D006801:Humans; D008954:Models, Biological; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism; D015398:Signal Transduction; D020691:rab GTP-Binding Proteins / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
D002966:Clathrin; D019061:src-Family Kinases; D016283:Proto-Oncogene Proteins p21(ras); D020691:rab GTP-Binding Proteins