title: CCR5 HIV-1 coreceptor activity. Role of cooperativity between residues in N-terminal extracellular and intracellular domains.
abstract: Human (H-) CCR5 is the primary coreceptor for ENV-mediated fusion by R5 strains of human immunodeficiency virus type 1, whereas mouse (M-) CCR5 lacks this function. An array of 23 H/M-CCR5 hybrids containing increasing amounts of H-CCR5 extending from the N terminus generated by random chimeragenesis had a biphasic pattern of coreceptor activity with JRFL and 89.6, revealing active regions in the N-terminal extracellular domain (N-ED) and at the junction of cytoplasmic loop 3. The M-CCR5 mutant in which divergent residues were replaced with the corresponding H-CCR5 N-ED sequence (NyYTsE) gained coreceptor function in fusion but not infection experiments. A M-CCR5 double mutant with substitution of human sequences for divergent residues from the N-ED and cytoplasmic loop 3 had augmented coreceptor activity in fusion assays and gain of function in infection experiments. The SIV-251 ENV utilized H- and M-CCR5 and variants. Flow cytometric analysis of M-CCR5 mutants and bifunctional receptors composed of CD4 domains fused to M-CCR5 mutants excluded the possibility that differences in coreceptor activity resulted from variations in cell surface expression. These results demonstrate that the coreceptor activity of the H-CCR5 N-ED is modulated by intracellular residues, illustrating the complexity of CCR5 requirements for interaction with ENV.
authors.affiliation: Henry Vogt Cancer Research Institute, University of Louisville, Louisville, Kentucky 40202, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: B
authors.initials: B
authors.lastname: Lee
authors.forename: J L
authors.initials: JL
authors.lastname: Murray
authors.forename: F
authors.initials: F
authors.lastname: Bonneau
authors.forename: Y
authors.initials: Y
authors.lastname: Sun
authors.forename: V
authors.initials: V
authors.lastname: Schweickart
authors.forename: T
authors.initials: T
authors.lastname: Zhang
authors.forename: S C
authors.initials: SC
authors.lastname: Peiper
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019713:Receptors, CCR5 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D019713:Receptors, CCR5; D011993:Recombinant Fusion Proteins