Isolation and characterization of laminin binding protein from regenerating rat liver plasma membrane

Interaction of rat hepatocytes with laminin, the major basement membrane adhesive glycoprotein was studied. Rat fetal hepatocytes attached more to laminin than adult hepatocytes. Laminin promoted attachment of fetal hepatocytes in a concentration dependent manner and showed saturable binding pattern. Hepatocytes from CCl4 induced regenerating rat liver also attached more to laminin. The pentapeptide YIGSR derived from laminin promoted attachment of adult and fetal hepatocytes, but to a lesser extent. A 67 kDa protein was isolated from the hepatic plasma membrane of CCl4 induced regenerating rat liver by affinity chromatography over laminin sepharose. This protein appeared to be relatively abundant in regenerating liver than in normal liver. The radioiodinated 67 kDa protein could be inserted into liposomes and these liposomes attached to coverslips coated with laminin in a concentration dependent manner in a divalent cation free medium. Its specificity for laminin was also revealed by absence of significant binding to fibronectin and collagen.