Molecular and Cellular Biology of Caveolae: Paradoxes and Plasticities

Abstract

Caveolae are 50–100 nm invaginations that represent an appendage or subcompartment of the plasma membrane. They are found in most cell types but are abundant in fibroblasts, adipocytes, endothelial cells, type I pneumocytes, epithelial cells, and smooth and striated muscle cells. Functionally, caveolae have been implicated in three major processes: endothelial transcytosis, potocytosis, and signal transduction. Caveolin, a 21–24 kD integral membrane protein, is a principal component of the caveolar membrane in vivo. Within caveolar microdomains, caveolin functions as a multivalent docking site for recruiting and sequestering signaling molecules. More specifically, caveolin interacts directly in a regulated manner with multiple lipid-modified signaling molecules (such as Src-tyrosine kinases, Gα subunits, and H-Ras), preferring the inactive conformation of these molecules. Here, we present a general overview of our current knowledge of caveolae and caveolin functioning and possible implications for treatment of human disease. (Trends Cardiovasc Med 1997;7:103–110). © 1997, Elsevier Science Inc.