title: A novel peptide antagonist of CXCR4 derived from the N-terminus of viral chemokine vMIP-II.
abstract: The viral macrophage inflammatory protein-II (vMIP-II) encoded by Kaposi's sarcoma-associated herpesvirus is unique among all known chemokines in that vMIP-II shows a broad-spectrum interaction with both CC and CXC chemokine receptors including CCR5 and CXCR4, two principal coreceptors for the cell entry of human immunodeficiency virus type 1 (HIV-1). To elucidate the mechanism of the promiscuous receptor interaction of vMIP-II, synthetic peptides derived from the N-terminus of vMIP-II were studied. In contrast to the full-length protein that recognizes both CXCR4 and CCR5, a peptide corresponding to residues 1-21 of vMIP-II (LGASWHRPDKCCLGYQKRPLP) was shown to strongly bind CXCR4, but not CCR5. The IC(50) of this peptide in competing with CXCR4 binding of (125)I-SDF-1alpha is 190 nM as compared to the IC(50) of 14.8 nM of native vMIP-II in the same assay. The peptide selectively prevented CXCR4 signal transduction and coreceptor function in mediating the entry of T- and dual-tropic HIV-1 isolates, but not those of CCR5. Further analysis of truncated peptide analogues revealed the importance of the first five residues for the activity with CXCR4. These results suggest that the N-terminus of vMIP-II is essential for its function via CXCR4. In addition, they reveal a possible mechanism for the distinctive interactions of vMIP-II with different chemokine receptors, a notion that may be further exploited to dissect the structural basis of its promiscuous biological function. Finally, the potent CXCR4 peptide antagonist shown here could serve as a lead for the development of new therapeutic agents for HIV infection and other immune system diseases.
authors.affiliation: Kimmel Cancer Institute, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: N
authors.initials: N
authors.lastname: Zhou
authors.forename: Z
authors.initials: Z
authors.lastname: Luo
authors.forename: J
authors.initials: J
authors.lastname: Luo
authors.forename: J W
authors.initials: JW
authors.lastname: Hall
authors.forename: Z
authors.initials: Z
authors.lastname: Huang
mesh_terms: D000595:Amino Acid Sequence; D019380:Anti-HIV Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D001665:Binding Sites; D002459:Cell Fusion; D002460:Cell Line; D002464:Cell Migration Inhibition; D054377:Chemokine CXCL12; D018925:Chemokines / Q000737:chemistry* / Q000378:metabolism; D019743:Chemokines, CXC / Q000037:antagonists & inhibitors / Q000502:physiology; D015497:HIV-1 / Q000472:pathogenicity; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D019718:Receptors, CXCR4 / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000502:physiology; D054380:Receptors, CXCR5; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D019380:Anti-HIV Agents; C515255:CXCL12 protein, human; C095085:CXCR5 protein, human; D054377:Chemokine CXCL12; D018925:Chemokines; D019743:Chemokines, CXC; D010446:Peptide Fragments; D019718:Receptors, CXCR4; D054380:Receptors, CXCR5; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine; C108059:vMIP-II