| Structural highlights
Disease
CXCR4_HUMAN Defects in CXCR4 are a cause of WHIM syndrome (WHIM) [MIM:193670; also known as warts, hypogammaglobulinemia, infections and myelokathexis. WHIM syndrome is an immunodeficiency disease characterized by neutropenia, hypogammaglobulinemia and extensive human papillomavirus (HPV) infection. Despite the peripheral neutropenia, bone marrow aspirates from affected individuals contain abundant mature myeloid cells, a condition termed myelokathexis.[1]
Function
CXCR4_HUMAN Receptor for the C-X-C chemokine CXCL12/SDF-1 that transduces a signal by increasing intracellular calcium ion levels and enhancing MAPK1/MAPK3 activation. Acts as a receptor for extracellular ubiquitin; leading to enhanced intracellular calcium ions and reduced cellular cAMP levels. Involved in hematopoiesis and in cardiac ventricular septum formation. Also plays an essential role in vascularization of the gastrointestinal tract, probably by regulating vascular branching and/or remodeling processes in endothelial cells. Involved in cerebellar development. In the CNS, could mediate hippocampal-neuron survival. Acts as a coreceptor (CD4 being the primary receptor) for HIV-1 X4 isolates and as a primary receptor for some HIV-2 isolates. Promotes Env-mediated fusion of the virus.[2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]
Publication Abstract from PubMed
CXC chemokine receptor 4 (CXCR4) is a well-established drug target and a key representative of the chemokine receptor family. Chemokine receptors tend to assemble, and this assembly plays a critical role in regulating their functions. However, structural information regarding the organization of these receptors remains limited. Here, we present the cryoelectron microscopy (cryo-EM) structure of a CXCR4 homo-tetramer. In this tetramer, each protomer interfaces with adjacent protomers via TM1/2 and TM5/6/7, aligning at a 90 degrees angle to assemble into a C4 rotationally symmetric arrangement. Each protomer allosterically regulates the others, with Q272 in the ECL3 loop interacting with K38 (TM1) and V99 (TM2) of the adjacent protomer, resulting in a mutually inhibitory configuration. These findings reveal an allosteric and antagonistic mechanism that prevents excessive activation, providing a structural framework for understanding the molecular mechanisms driving CXCR4 self-assembly and offering insights that could inspire further therapeutic strategies.
Structural basis of CXCR4 assembly and regulation.,Liu A, Liu Y, Ye RD Cell Rep. 2025 Feb 25;44(2):115255. doi: 10.1016/j.celrep.2025.115255. Epub 2025 , Jan 31. PMID:39891908[14]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Hernandez PA, Gorlin RJ, Lukens JN, Taniuchi S, Bohinjec J, Francois F, Klotman ME, Diaz GA. Mutations in the chemokine receptor gene CXCR4 are associated with WHIM syndrome, a combined immunodeficiency disease. Nat Genet. 2003 May;34(1):70-4. PMID:12692554 doi:10.1038/ng1149
- ↑ Herzog H, Hort YJ, Shine J, Selbie LA. Molecular cloning, characterization, and localization of the human homolog to the reported bovine NPY Y3 receptor: lack of NPY binding and activation. DNA Cell Biol. 1993 Jul-Aug;12(6):465-71. PMID:8329116
- ↑ Jazin EE, Yoo H, Blomqvist AG, Yee F, Weng G, Walker MW, Salon J, Larhammar D, Wahlestedt C. A proposed bovine neuropeptide Y (NPY) receptor cDNA clone, or its human homologue, confers neither NPY binding sites nor NPY responsiveness on transfected cells. Regul Pept. 1993 Sep 22;47(3):247-58. PMID:8234909
- ↑ Feng Y, Broder CC, Kennedy PE, Berger EA. HIV-1 entry cofactor: functional cDNA cloning of a seven-transmembrane, G protein-coupled receptor. Science. 1996 May 10;272(5263):872-7. PMID:8629022
- ↑ Bleul CC, Farzan M, Choe H, Parolin C, Clark-Lewis I, Sodroski J, Springer TA. The lymphocyte chemoattractant SDF-1 is a ligand for LESTR/fusin and blocks HIV-1 entry. Nature. 1996 Aug 29;382(6594):829-33. PMID:8752280 doi:10.1038/382829a0
- ↑ Oberlin E, Amara A, Bachelerie F, Bessia C, Virelizier JL, Arenzana-Seisdedos F, Schwartz O, Heard JM, Clark-Lewis I, Legler DF, Loetscher M, Baggiolini M, Moser B. The CXC chemokine SDF-1 is the ligand for LESTR/fusin and prevents infection by T-cell-line-adapted HIV-1. Nature. 1996 Aug 29;382(6594):833-5. PMID:8752281 doi:10.1038/382833a0
- ↑ Brelot A, Heveker N, Adema K, Hosie MJ, Willett B, Alizon M. Effect of mutations in the second extracellular loop of CXCR4 on its utilization by human and feline immunodeficiency viruses. J Virol. 1999 Apr;73(4):2576-86. PMID:10074102
- ↑ Cheng ZJ, Zhao J, Sun Y, Hu W, Wu YL, Cen B, Wu GX, Pei G. beta-arrestin differentially regulates the chemokine receptor CXCR4-mediated signaling and receptor internalization, and this implicates multiple interaction sites between beta-arrestin and CXCR4. J Biol Chem. 2000 Jan 28;275(4):2479-85. PMID:10644702
- ↑ Brelot A, Heveker N, Montes M, Alizon M. Identification of residues of CXCR4 critical for human immunodeficiency virus coreceptor and chemokine receptor activities. J Biol Chem. 2000 Aug 4;275(31):23736-44. PMID:10825158 doi:10.1074/jbc.M000776200
- ↑ Berchiche YA, Chow KY, Lagane B, Leduc M, Percherancier Y, Fujii N, Tamamura H, Bachelerie F, Heveker N. Direct assessment of CXCR4 mutant conformations reveals complex link between receptor structure and G(alpha)(i) activation. J Biol Chem. 2007 Feb 23;282(8):5111-5. Epub 2006 Dec 29. PMID:17197449 doi:10.1074/jbc.C600270200
- ↑ Busillo JM, Armando S, Sengupta R, Meucci O, Bouvier M, Benovic JL. Site-specific phosphorylation of CXCR4 is dynamically regulated by multiple kinases and results in differential modulation of CXCR4 signaling. J Biol Chem. 2010 Mar 5;285(10):7805-17. doi: 10.1074/jbc.M109.091173. Epub 2010 , Jan 4. PMID:20048153 doi:10.1074/jbc.M109.091173
- ↑ Saini V, Marchese A, Majetschak M. CXC chemokine receptor 4 is a cell surface receptor for extracellular ubiquitin. J Biol Chem. 2010 May 14;285(20):15566-76. doi: 10.1074/jbc.M110.103408. Epub, 2010 Mar 12. PMID:20228059 doi:10.1074/jbc.M110.103408
- ↑ Malik R, Marchese A. Arrestin-2 interacts with the endosomal sorting complex required for transport machinery to modulate endosomal sorting of CXCR4. Mol Biol Cell. 2010 Jul 15;21(14):2529-41. doi: 10.1091/mbc.E10-02-0169. Epub, 2010 May 26. PMID:20505072 doi:10.1091/mbc.E10-02-0169
- ↑ Liu A, Liu Y, Ye RD. Structural basis of CXCR4 assembly and regulation. Cell Rep. 2025 Feb 25;44(2):115255. PMID:39891908 doi:10.1016/j.celrep.2025.115255
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