Characterization of a laminin receptor from human breast carcinoma tissue

Human breast carcinoma contains high-affinity receptors for the basement membrane glycoprotein laminin. Plasma membranes isolated from tissue samples of human breast carcinoma exhibit specific, saturable, reversible, and displaceable binding to laminin. Fibronectin, collagen, and serum proteins fail to displace this bound laminin. Scatchard analysis is linear with a Kd of 1.8 X 10(-9) M. The laminin receptor, isolated and purified 1200-fold by laminin-affinity chromatography, exhibits a molecular weight of 67 000 daltons as determined by gel electrophoresis. The receptor was verified to be located on the cell surface of the invading breast carcinoma cells by immunohistologic studies utilizing a peroxidase-conjugated fragment of the laminin molecule which contained the receptor-binding domain.