title: LD78beta, a non-allelic variant of human MIP-1alpha (LD78alpha), has enhanced receptor interactions and potent HIV suppressive activity.
abstract: Chemokines play diverse roles in inflammatory and non-inflammatory situations via activation of heptahelical G-protein-coupled receptors. Also, many chemokine receptors can act as cofactors for cellular entry of human immunodeficiency virus (HIV) in vitro. CCR5, a receptor for chemokines MIP-1alpha (LD78alpha), MIP-1beta, RANTES, and MCP2, is of particular importance in vivo as polymorphisms in this gene affect HIV infection and rate of progression to AIDS. Moreover, the CCR5 ligands can prevent HIV entry through this receptor and likely contribute to the control of HIV infection. Here we show that a non-allelic isoform of human MIP-1alpha (LD78alpha), termed LD78beta or MIP-1alphaP, has enhanced receptor binding affinities to CCR5 (approximately 6-fold) and the promiscuous beta-chemokine receptor, D6 (approximately 15-20-fold). We demonstrate that a proline residue at position 2 of MIP-1alphaP is responsible for this enhanced activity. Moreover, MIP-1alphaP is by far the most potent natural CCR5 agonist described to date, and importantly, displays markedly higher HIV1 suppressive activity than all other human MIP-1alpha isoforms examined. In addition, while RANTES has been described as the most potent inhibitor of CCR5-mediated HIV entry, MIP-1alphaP was as potent as, if not more potent than, RANTES in HIV-1 suppressive assays. This property suggests that MIP-1alphaP may be of importance in controlling viral spread in HIV-infected individuals.
authors.affiliation: Beatson Institute for Cancer Research, CRC Beatson Laboratories, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD Scotland, United Kingdom.
authors.forename: R J
authors.initials: RJ
authors.lastname: Nibbs
authors.forename: J
authors.initials: J
authors.lastname: Yang
authors.forename: N R
authors.initials: NR
authors.lastname: Landau
authors.forename: J H
authors.initials: JH
authors.lastname: Mao
authors.forename: G J
authors.initials: GJ
authors.lastname: Graham
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019380:Anti-HIV Agents / Q000378:metabolism* / Q000494:pharmacology; D002460:Cell Line; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D018946:Chemokine CCL5 / Q000494:pharmacology; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D019402:Macrophage Inflammatory Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D051379:Mice; D008969:Molecular Sequence Data; D011485:Protein Binding; D054389:Receptors, CCR1; D054447:Receptors, CCR10; D019713:Receptors, CCR5 / Q000378:metabolism; D019707:Receptors, Chemokine / Q000378:metabolism*; D000097628:Chemokine Receptor D6
chemical_list: D019380:Anti-HIV Agents; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D018946:Chemokine CCL5; D019402:Macrophage Inflammatory Proteins; D054389:Receptors, CCR1; D054447:Receptors, CCR10; D019713:Receptors, CCR5; D019707:Receptors, Chemokine; D000097628:Chemokine Receptor D6; C515300:CCR1 protein, human; C515301:Ccr1 protein, mouse; C080633:macrophage inflammatory protein 1alpha receptor