| Structural highlights
Function
[CCL4_HUMAN] Monokine with inflammatory and chemokinetic properties. Binds to CCR5. One of the major HIV-suppressive factors produced by CD8+ T-cells. Recombinant MIP-1-beta induces a dose-dependent inhibition of different strains of HIV-1, HIV-2, and simian immunodeficiency virus (SIV). The processed form MIP-1-beta(3-69) retains the abilities to induce down-modulation of surface expression of the chemokine receptor CCR5 and to inhibit the CCR5-mediated entry of HIV-1 in T-cells. MIP-1-beta(3-69) is also a ligand for CCR1 and CCR2 isoform B.[1] [2] [3]
Publication Abstract from PubMed
Macrophage inflammatory protein-1 (MIP-1), MIP-1alpha (CCL3) and MIP-1beta (CCL4) are chemokines crucial for immune responses towards infection and inflammation. Both MIP-1alpha and MIP-1beta form high-molecular-weight aggregates. Our crystal structures reveal that MIP-1 aggregation is a polymerization process and human MIP-1alpha and MIP-1beta form rod-shaped, double-helical polymers. Biophysical analyses and mathematical modelling show that MIP-1 reversibly forms a polydisperse distribution of rod-shaped polymers in solution. Polymerization buries receptor-binding sites of MIP-1alpha, thus depolymerization mutations enhance MIP-1alpha to arrest monocytes onto activated human endothelium. However, same depolymerization mutations render MIP-1alpha ineffective in mouse peritoneal cell recruitment. Mathematical modelling reveals that, for a long-range chemotaxis of MIP-1, polymerization could protect MIP-1 from proteases that selectively degrade monomeric MIP-1. Insulin-degrading enzyme (IDE) is identified as such a protease and decreased expression of IDE leads to elevated MIP-1 levels in microglial cells. Our structural and proteomic studies offer a molecular basis for selective degradation of MIP-1. The regulated MIP-1 polymerization and selective inactivation of MIP-1 monomers by IDE could aid in controlling the MIP-1 chemotactic gradient for immune surveillance.
Polymerization of MIP-1 chemokine (CCL3 and CCL4) and clearance of MIP-1 by insulin-degrading enzyme.,Ren M, Guo Q, Guo L, Lenz M, Qian F, Koenen RR, Xu H, Schilling AB, Weber C, Ye RD, Dinner AR, Tang WJ EMBO J. 2010 Oct 19. PMID:20959807[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Cocchi F, DeVico AL, Garzino-Demo A, Arya SK, Gallo RC, Lusso P. Identification of RANTES, MIP-1 alpha, and MIP-1 beta as the major HIV-suppressive factors produced by CD8+ T cells. Science. 1995 Dec 15;270(5243):1811-5. PMID:8525373
- ↑ Garlisi CG, Xiao H, Tian F, Hedrick JA, Billah MM, Egan RW, Umland SP. The assignment of chemokine-chemokine receptor pairs: TARC and MIP-1 beta are not ligands for human CC-chemokine receptor 8. Eur J Immunol. 1999 Oct;29(10):3210-5. PMID:10540332 doi:http://dx.doi.org/10.1002/(SICI)1521-4141(199910)29:10<3210::AID-IMMU3210>3.0.CO;2-W
- ↑ Guan E, Wang J, Roderiquez G, Norcross MA. Natural truncation of the chemokine MIP-1 beta /CCL4 affects receptor specificity but not anti-HIV-1 activity. J Biol Chem. 2002 Aug 30;277(35):32348-52. Epub 2002 Jun 17. PMID:12070155 doi:http://dx.doi.org/10.1074/jbc.M203077200
- ↑ Ren M, Guo Q, Guo L, Lenz M, Qian F, Koenen RR, Xu H, Schilling AB, Weber C, Ye RD, Dinner AR, Tang WJ. Polymerization of MIP-1 chemokine (CCL3 and CCL4) and clearance of MIP-1 by insulin-degrading enzyme. EMBO J. 2010 Oct 19. PMID:20959807 doi:10.1038/emboj.2010.256
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