Cell adhesive sequences in mouse laminin beta 1 chain

Laminin-1, a major component of the basement membrane, consists of three di fferent chains, alpha 1, beta 1, and gamma 1. We sought to identify cell ad hesive sequences from the mouse laminin beta 1 chain by testing HT-1080 fib rosarcoma and B16-F10 melanoma cells for binding to 187 overlapping; synthe tic peptides which covered the entire chain. Fourteen peptides showed cell adhesive activities with either peptide-conjugated Sepharose beads or pepti de-coated plates or both, Additional cells, including neuronal, endothelial , and salivary gland cells, showed biological responses in a cell type-spec ific manner. B-7, B-133, and B-160 showed the most potent cell attachment. Cell binding on three peptides (B-34, B-133, and B-160) was inhibited by ED TA. Cell adhesion to 11 of the 12 active peptides was inhibited to varying degrees by heparin. Of the 17 active peptides identified in the laminin bet a 1 chain in this and other studies, 8 are clustered on the amino terminal globular domain, suggesting a possible important role in cell binding for t his domain that may be multifunctional. These data demonstrate that the lam inin beta 1 chain has multiple active sites for cell adhesion, some of whic h are cell-type specific. (C) 2000 Academic Press.