| 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] GFP_AEQVI Energy-transfer acceptor. Its role is to transduce the blue chemiluminescence of the protein aequorin into green fluorescent light by energy transfer. Fluoresces in vivo upon receiving energy from the Ca(2+)-activated photoprotein aequorin.
Publication Abstract from PubMed
Activation of the chemokine receptor CXCR4 by its chemokine ligand CXCL12 regulates diverse cellular processes. Previously reported crystal structures of CXCR4 revealed the architecture of an inactive, homodimeric receptor. However, many structural aspects of CXCR4 remain poorly understood. Here, we use cryo-electron microscopy to investigate various modes of human CXCR4 regulation. CXCL12 activates CXCR4 by inserting its N terminus deep into the CXCR4 orthosteric pocket. The binding of US Food and Drug Administration-approved antagonist AMD3100 is stabilized by electrostatic interactions with acidic residues in the seven-transmembrane-helix bundle. A potent antibody blocker, REGN7663, binds across the extracellular face of CXCR4 and inserts its complementarity-determining region H3 loop into the orthosteric pocket. Trimeric and tetrameric structures of CXCR4 reveal modes of G-protein-coupled receptor oligomerization. We show that CXCR4 adopts distinct subunit conformations in trimeric and tetrameric assemblies, highlighting how oligomerization could allosterically regulate chemokine receptor function.
Structural insights into CXCR4 modulation and oligomerization.,Saotome K, McGoldrick LL, Ho JH, Ramlall TF, Shah S, Moore MJ, Kim JH, Leidich R, Olson WC, Franklin MC Nat Struct Mol Biol. 2024 Sep 23. doi: 10.1038/s41594-024-01397-1. PMID:39313635[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
- ↑ Saotome K, McGoldrick LL, Ho JH, Ramlall TF, Shah S, Moore MJ, Kim JH, Leidich R, Olson WC, Franklin MC. Structural insights into CXCR4 modulation and oligomerization. Nat Struct Mol Biol. 2024 Sep 23. PMID:39313635 doi:10.1038/s41594-024-01397-1
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