MEMBERS OF THE LOW-DENSITY-LIPOPROTEIN RECEPTOR FAMILY MEDIATE CELL ENTRY OF A MINOR-GROUP COMMON COLD VIRUS

A protein binding to a minor-group human rhinovirus (HRV2) was purifie d from HeLa cell culture supernatant. The amino acid sequences of tryp tic peptides showed identity with the human low density lipoprotein (L DL) receptor (LDLR). LDL and HRV2 mutually competed for binding sites on human fibroblasts. Cells down-regulated for LDLR expression yielded much less HRV2 upon infection than cells with up-regulated LDLR. Viru s also bound to the large subunit of the alpha(2)-macroglobulin recept or/LDLR-related protein (alpha(2)MR/LRP). LDLR-deficient fibroblasts y ielded considerably less virus in the presence of receptor-associated protein (RAP), providing evidence that alpha(2)MR/LRP also acts as a m inor group HRV receptor.