Abstract
Following a retrospective view on development of the present concept of microdomain, current views of multiple microdomains are briefly presented. Based on physical properties of membrane components, some lipids are clustered, segregated from other lipids, and organized with cytoplasmic lipophilic signal transducer molecules and with transmembrane receptors with hydrophobic domain, and their associated partners. Typical examples are: (i) glycosphingolipids (GSLs) and sphingomyelin organized with cSrc, Src family kinases, and small G-proteins, collectively termed “glycosignaling domain (GSD)” and involved in GSL-dependent cell adhesion and signaling; (ii) caveolae and caveolar membrane, characterized by high content of cholesterol and caveolin, organized with GPI-anchors and signal transducers, and involved in endocytosis and signal transduction; (iii) integrins and tetraspan membrane proteins (TMP) complexed with some type of GSL; (iv) growth factor receptors with tyrosine kinases complexed with cholesterol-enriched domain, with or without some type of GSL. The defined composition and association of signal transducer molecules in microdomain iii and iv is yet unclear. Relative quantity and proportion of these types of microdomain differs and is characteristic for different types of cells.
