?1-Integrin-Mediated Neuronal Responses to Extracellular Matrix Proteins

Abstract

Immunologic and biochemical studies demonstrate that beta 1-class integrin heterodimers mediate attachment and neurite outgrowth by primary neurons and neuronal cell lines in response to neurite-promoting ECM molecules. Individual cells are likely to express several alpha beta 1 integrins, each possessing unique ligand specificities. In some cases, a cell may express two beta 1 integrins that recognize different binding domains in a single ECM ligand, as appears to be the case for the alpha 3 beta 1 and alpha 1 beta 1 integrins on PC12 cells. Thus, the responses of a neuron to even a single ligand may be regulated by the combined action of several receptors. Finally, preliminary studies suggest that neurons can regulate the ligand specificity of individual integrin heterodimers (e.g., alpha 1 beta 1). Given the tremendous diversity in the extracellular matrix surrounding them, it is not surprising that neurons possess intrinsic factors that dictate if and how they respond to a particular ECM component.