TYPE-XVII COLLAGEN AND COLLAGEN-LIKE MOLECULES - RELATED BY MORE THANA COMMON MOTIF

Historically, collagens have been defined as extracellular matrix stru ctural proteins whose sequence is characterized by many repeats of a t hree amino acid unit, GLY-X-Y: However; the latter motif has been iden tified in certain domains of number of other proteins including the Cl q subunit of complement, the collectins, the asymmetric form of acetyl cholinesterase, ficolin and the macrophage scavenger receptors. We des cribe these molecules and discuss both their structure and their putat ive functions. Intriguingly, these proteins show similarity to a 180 k D protein component of an epithelial cell/matrix anchorage device call ed the hemidesmosome. The latter protein is now considered a bona fide member of the collagen superfamily and has been termed type XVII coll agen, despite the fact that it is a non-secreted transmembrane protein . We review recent studies on type XVII collagen which provide clues t o its potential protein-protein interactions as well as its role in th e pathogenesis of two human shin diseases. (C) 1996 Academic Press Ltd