Retrovirus receptor PiT-1 of the Felis catus

We isolated a cDNA encoding a feline homolog of human PiT-1, a sodium-depen dent phosphate symporter which is utilized by gibbon ape leukemia virus (GA LV) as a receptor for entry into host cells. The overall homology between t he human and feline receptors is 92 and 93% at the nucleotide and deduced a mino acid levels, respectively. Hydropathy analyses implied ten potential m embrane spanning regions and, in analogy to human and murine homologs, five extracellular and four intracellular loops. Strikingly, the amino acid seq uence of the fourth extracellular loop, which is critical for GALV surface glycoprotein binding, has complete identity between the human and feline Pi T-1s, while the mouse PiT-1, nonfunctional for GALV entry, is quite diverge nt. Ectopic expression of the feline PiT-1 in guinea pig cells, which are n onpermissive to feline leukemia virus (FeLV), subgroup B virus, conferred s usceptibility to FeLV-B infection confirming the functional ability of the cloned product to serve as a receptor for a natural retrovirus of the homol ogous species. (C) 1998 Elsevier Science B.V. All rights reserved.