A pentapeptide from the laminin B1 chain mediates cell adhesion and binds the 67,000 laminin receptor.

Laminin promotes epithelial cell adhesion in part through a site of nine amino acids CDPGYIGSR on the B1 chain. Using smaller synthetic peptides from this sequence as well as various peptides with amino acid substitutions, we find that the minimum sequence necessary for efficient cell adhesion as well as receptor binding is YIGSR. The deletion of tyrosine or the substitution of arginine in the peptides resulted in a significant loss of activity. The presence of an amide group on the terminal arginine of either peptide increases activity significantly. YIGSR is active in promoting the adhesion of a variety of epithelial cells; however, it is inactive with chondrocytes, fibroblasts, and osteoblasts.