The caveolin gene family has three members in vertebrates: caveolin-1, caveolin-2, and caveolin-3. So far, most caveolin-related research has been conducted in mammals, but the proteins have also been found in other animals, including Xenopus laevis, Fugu rubripes, and Caenorhabditis elegans. Caveolins can serve as protein markers of caveolae (‘little caves’), invaginations in the plasma membrane 50-100 nanometers in | Protein family review The caveolin proteins Terence M Williams and Michael P Lisanti Addresses Department of Molecular Pharmacology and The Albert Einstein Cancer Center Albert Einstein College of Medicine 1300 Morris Park Avenue Bronx NY 10461 USA. Correspondence Michael P Lisanti. E-mail lisanti@ Published I March 2004 Genome Biology 2004 5 214 The electronic version of this article is the complete one and can be found online at http 2004 5 3 214 2004 BioMed Central Ltd Summary The caveolin gene family has three members in vertebrates caveolin-1 caveolin-2 and caveolin-3. So far most caveolin-related research has been conducted in mammals but the proteins have also been found in other animals including Xenopus laevis Fugu rubripes and Caenorhabditis elegans. Caveolins can serve as protein markers of caveolae little caves invaginations in the plasma membrane 50-100 nanometers in diameter. Caveolins are found predominantly at the plasma membrane but also in the Golgi the endoplasmic reticulum in vesicles and at cytosolic locations. They are expressed ubiquitously in mammals but their expression levels vary considerably between tissues. The highest levels of caveolin-1 also called caveolin Cav-1 and VIP21 are found in terminally-differentiated cell types such as adipocytes endothelia smooth muscle cells and type I pneumocytes. Caveolin-2 Cav-2 is colocalized and coexpressed with Cav-1 and requires Cav-1 for proper membrane targeting the Cav-2 gene also maps to the same chromosomal region as Cav-1 in humans . Caveolin-3 Cav-3 has greater protein-sequence similarity to Cav-1 than to Cav-2 but it is expressed mainly in muscle cells including smooth skeletal and cardiac myocytes. Caveolins participate in many important cellular processes including vesicular transport cholesterol homeostasis signal transduction and tumor suppression. Gene organization and evolutionary history Research into caveolae began with their morphological .
