The cell biology of thrombospondin-1

Thrombospondin-1 (TSP-1) is a matricellular protein that regulates cellular phenotype during tissue genesis and repair. It acts as a molecular facilit ator by bringing together cytokines, growth factors, matrix components, mem brane receptors and extracellular proteases. TSP-1 binds to a wide variety of integrin and non-integrin cell surface receptors. The binding sites for these receptors on TSP-1 are dispersed throughout the molecule, with most d omains binding multiple receptors. In some cases, TSP-1 binds to multiple r eceptors concurrently, and recent data indicate that there is cross-talk be tween the receptor systems. Thus, TSP-1 may function to direct the clusteri ng of receptors to specialized domains for adhesion and signal transduction . (C) 2000 Elsevier Science B.V. International Society of Matrix Biology. A ll rights reserved.