Integrin ligands at a glance

Abstract

Integrin function has been determined through a combination of cell biological and genetic analyses. On the cytoplasmic face of the plasma membrane, integrin occupancy coordinates the assembly of cytoskeletal polymers and signalling complexes; on the extracellular face, integrins engage either extracellular matrix macromolecules or counter-receptors on adjacent cell surfaces. These bidirectional linkages impose spatial restrictions on signalling and extracellular matrix assembly, and thereby integrate cells with their microenvironment. In turn, membrane-proximal interactions initiate more distal functions such as tissue patterning (extracellularly) and cell fate determination (intracellularly). Genetic analyses of engineered or natural mutations have confirmed key roles for integrins in tissue integrity, cell trafficking, and differentiation (Bouvard et al., 2001; Bokel and Brown, 2002).