Isolation of a cell surface receptor protein for laminin from murine fibrosarcoma cells.

Abstract

We used affinity chromatography to isolate a specific laminin-binding protein from murine fibrosarcoma cells. These cells bind exogenous laminin to their surface with high affinity ( K~ = 2 X 10-9M for laminin) with -5 x 104 sites per cell. Laminin affinity chromatography of [aSS]methioninelabeled cell extracts produced two distinct proteins. One was identified as Type IV (basement membrane) collagen based on its migration pattern on SDS gels and bacterial collagenase sensitivity. The other protein, which migrates as a single band or closely spaced doublet on reduced SDS gels, has a reduced molecular weight of 69,000. Using a nitrocellulose filter disk assay, we found that the latter protein specifically bound 12~l-laminin with the same high affinity ( Kd = 2 X 10-9M for laminin) as did intact fibrosarcoma cells. By iodinating intact cells, we demonstrated that this laminin-binding protein is on the cell surface. We conclude that this protein with reduced molecular weight of 69,000 is a subunit or component of a larger cell surface receptor protein for laminin in this fibrosarcoma model. This laminin receptor may mediate the interaction of the cell with its extracellular matrix.

Laminin-1-induced migration of multiple myeloma cells involves the high-affinity 67 kD laminin receptor

“…Invasion of the subendothelial basement membrane is mediated in part by interactions of tumour cells with laminin via specific cell surface receptors (Ramos et al, 1991). The 67 kD laminin-binding protein (67LR) represents a nonintegrin-binding protein which binds LN with high affinity (Malinoff and Wicha, 1983). Expression of 67LR has been shown to be increased in neoplastic cells as compared to their normal counterparts and directly correlates with an enhanced invasive and metastatic potential (D'Errico et al, 1991;Kim et al, 1998).…”

A synthetic peptide derived from the carboxy terminus of the laminin A chain represents a binding site for the alpha 3 beta 1 integrin

“…Interactions of cells with laminin have been shown to be mediated by both integrin-type cell surface receptors (Hemler et al, 1987;Gehlsen et al, 1989;Sonnenberg et al, 1988;Ignatius et al, 1990) and by other nonintegrin molecules including a 67-kD protein (Malinoff and Wicha, 1983;Wewer et al ., 1987) and 01,4 galactosyltransferase (Begovac et al ., 1991) .…”

Different Isoforms of the Non-Integrin Laminin Receptor Are Present in Mouse Brain and Bind PrP

“…One of these isoforms, the 67 kDa high affinity laminin receptor (LR: presumably the mature form of the receptor), is thought to arise from the heterodimerization of its precursor molecule, the 37 kDa LRP, with a still unidentified molecule (Buto et al, 1998). The 67 kDa LR is believed to be the functional isoform of the receptor regarding its ability to mediate strong attachement of cells to laminin (Lesot et al, 1983;Malinoff and Wicha, 1983;Rao et al, 1983), to be overexpressed on cancer cell sufaces, and to promote the invasive and metastatic capacity of these cells (Menard et al, 1997). Thus, it is of crucial importance to investigate whether this isoform is normally expressed in mouse brain and whether this isoform binds PrP.…”