A novel fibronectin receptor with an unexpected subunit composition (alpha v beta 1).

The integrins are a family of heterodimeric cell surface receptors for extracellular matrix molecules. An analysis of integrin subunits expressed by a number of cell lines identified a novel heterodimer. The alpha subunit of this integrin was immunologically and electrophoretically indistinguishable from the vitronectin receptor alpha subunit (alpha v) and the beta subunit was indistinguishable from beta 1. Affinity chromatography experiments and cell adhesion assays indicated that this receptor complex is a new fibronectin receptor. Its unexpected subunit composition demonstrates the importance of the beta subunit in determining the ligand specificity of integrins and suggests that the current integrin classification scheme needs revision.