Endothelial cells use alpha 2 beta 1 integrin as a laminin receptor.

Abstract

Abstract. Human umbilical vein endothelial cells attach and spread on laminin-coated substrates. Affinity chromatography was used to identify the attachment receptor. Fractionation of extracts from surfaceiodinated endothelial cells on human lamininSepharose yielded a heterodimeric complex, the subunits of which migrated with molecular sizes corresponding to 160/120 kD and 160/140 kD under nonreducing and reducing conditions, respectively. The purified receptor bound to laminin and slightly less to fibronectin and type IV collagen in a radioreceptor assay. This endothelial cell laminin receptor was classified as an t~zB, integrin because monoclonal and polyclonal antibodies directed against the ct2 and/3, subunits immunoprecipitated the receptor. Cytofluorometric analysis arid immunoprecipitation showed that the ix2 subunit is an abundant integrin ~t subunit in the endothelial cells and that the ot subunits associated with laminin binding in other types of cells are expressed in these cells only at low levels. The ,v~, integrin appears to be a major receptor for laminin in the endothelial cells, because an anti-ix2 monoclonal antibody inhibited the attachment of the endothelial cells to human laminin. These results define a new role for the o~2 subunit in laminin binding and suggest that the ligand specificity of the tx2/3t integrin, which is known as a collagen receptor in other types of cells, can be modulated by cell type-specific factors to include laminin binding.

Altered cell-matrix contact: a prerequisite for breast cancer metastasis?

“…Primary breast cancer cell-matrix adhesion of nodenegative women was significantly reduced compared with control wells using the paired Wilcoxon test (Figure 5). Inhibition of breast cancer cell adhesion by monoclonal antibodies in nodenegative women was consistent with previous knowledge of integrin receptor-ligand interactions (Hynes, 1992 (Languino et al, 1989) and collagen (Santoro et al, 1988 to be clarified. The mechanism by which integrin receptors are able to recognize multiple ligands is as yet uncertain.…”

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

“…In this study, we report that other cell types including MG-63, C8161, and IMR-90 cells also adhere to peptide GD-6. These cells have been well characterized with respect to their integrin repertoire, and they all have been shown to express the a3ß, integrin, and other laminin-binding integrins on their surfaces (Gehlsen et al ., 1989;Languino et al, 1989). Human keratinocytes have also been shown to express a3ß,, and recently, epiligrin, a new potential ligand for a3ß1 has been isolated from keratinocyte matrices (Carter et al ., 1991) .…”

“…Several integrins are known to be receptors for laminin including a,ß,, a2ß,, a3ß1 , a6ß,, a7ß, (Tomaselli et al, 1990;Languino et al, 1989;Gehlsen et al, 1989;Sonnenberg et al, 1988Sonnenberg et al, , 1991Kramer et al ., 1991), and a4ß3 (Sonnenberg et al, 1990;Kramer et al ., 1990). In addition, the a,ß,, a2ß,, and a3ß, integrins also bind to other ex-© The Rockefeller University Press, 0021-9525/92/04/449/11 $2 .00 The Journal of Cell Biology, Volume 117, Number 2, April 1992 449-459 sion to laminin-coated surfaces .…”

Laminin-binding integrin alpha 7 beta 1: functional characterization and expression in normal and malignant melanocytes.

“…In addition, a cryptic Arg-Gly-Asp(RGD)-dependent site for aC%3 is generated in the P1 fragment (Aumailley et aL, 1 990a;Sonnenberg et al, 1990). The a2f1 integrin also binds laminin Languino et a/., 1989;Kramer et al, 1990), although the specific binding site on laminin for this receptor has not as yet been defined.…”