Actin binds to the cytoplasmic tail of alpha(1) subunit of integrin in hepatocytes

alpha(1)beta(1)-Integrin is a common receptor for laminin and collagen IV o n hepatocytes. The interactions of intracellular domain of integrins with c ytoplasmic elements are critical in the initiation and transduction of sign als. In older to understand the nature of cytoplasmic components that can i nteract with cytoplasmic domain of alpha(1) integrin, cytoplasmic extracts of monolayers of rat hepatocytes were subjected to chromatography over an a ffinity column prepared by coupling a 60-mer synthetic cytoplasmic tail of alpha(1) subunit. SDS-PAGE analysis of the eluate showed the presence of a 47 kDa protein. Dot-Blot assay using radio-iodinated 47 kDa protein showed the binding of the protein to 60-mer C tail in a concentration dependent ma nner. Immunoblot analysis using specific antibodies showed that the 47 kDa protein is actin.