"The major glycoprotein component of animal cell basement membranes, laminin, is involved in a variety of cellular activities, including cell adhesion, differentiation, and mito- genesis, that are mediated by the interaction of laminin with specific cell-surfacereceptors. A laminin-binding protein with an apparent molecular mass of 68 to 72 kD was first char- acterized in mammalian tumor cells and considered as “the laminin receptor” (Liotta et al., 1986; Wewer et al., 1986). Severa1 putative cDNA clones encoding this protein have been isolated from mammals (Yow et al., 1988; Rao et al., 1989; Van den Ouweland et al., 1989; Grosso et al., 1991). A11 the clones contained an open reading frame coding for a highly conserved polypeptide with a calculated molecular mass of 33 kD. Independently, a cDNA encoding an identical polypeptide was isolated from mouse tumor cells (Makrides et al., 1988), but the expressed protein, named factor p40, was shown to be a component of the translation machinery (Auth and Brawerman, 1992). Recently, DNA-deduced amino acid sequences exhibiting homology with the previ- ously characterized 33-kD ”laminin receptor” were identified from hydra (Keppel and Schaller, 1991), Drosophila (M.B. Melnick, T.B. Chou, and N. Perrimon, accession No. M90422), and yeast (J. Miles and T.G. Formosa, accession No. M88277)."