title: Feline leukemia virus T entry is dependent on both expression levels and specific interactions between cofactor and receptor.
abstract: Feline leukemia virus (FeLV) subgroup T uses both a multiple membrane-spanning receptor, FePit1, and a soluble cofactor, FeLIX, to enter feline cells. FeLIX is expressed from endogenous FeLV-related sequence and resembles the receptor binding domain (RBD) of the viral envelope protein. It remains unclear whether FeLV-T receptor activity requires specific residues within FePit1 and FeLIX and/or a threshold level of receptor/cofactor expression. To address this, we examined FeLV-T infection of cells expressing variable levels of FePit1 and other gammaretroviral receptors in the presence of variable amounts of soluble cofactor, either RBD or the envelope surface subunit (SU). Cofactor-receptor pairs fall into three groups with regard to mediating FeLV-T infection: those that are efficient at all concentrations tested, such as FePit1 and FeLIX; those requiring high expression of both cofactor and receptor; and those that are non-functional as receptors even at high expression. This suggests that both expression levels and specific interactions with receptor and cofactor are critical for mediating entry of FeLV-T.
authors.affiliation: Program in Molecular and Cellular Biology, University of Washington, Seattle, WA 98109, USA.
authors.forename: Heather H
authors.initials: HH
authors.lastname: Cheng
authors.forename: Maria M
authors.initials: MM
authors.lastname: Anderson
authors.forename: Julie
authors.initials: J
authors.lastname: Overbaugh
mesh_terms: D000818:Animals; D002460:Cell Line; D005347:Fibroblasts / Q000821:virology; D006801:Humans; D005256:Leukemia Virus, Feline / Q000254:growth & development / Q000502:physiology*; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D011991:Receptors, Virus / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism*; D053586:Virus Internalization
chemical_list: C405955:FeLIX protein, feline leukemia virus; D008565:Membrane Proteins; D011991:Receptors, Virus; D014759:Viral Envelope Proteins