Closely related, yet unique: Distinct homo- and heterodimerization patterns of G protein coupled chemokine receptors and their fine-tuning by cholesterol

PLoS Comput Biol. 2018 Mar 12;14(3):e1006062. doi: 10.1371/journal.pcbi.1006062. eCollection 2018 Mar.

Abstract

Chemokine receptors, a subclass of G protein coupled receptors (GPCRs), play essential roles in the human immune system, they are involved in cancer metastasis as well as in HIV-infection. A plethora of studies show that homo- and heterodimers or even higher order oligomers of the chemokine receptors CXCR4, CCR5, and CCR2 modulate receptor function. In addition, membrane cholesterol affects chemokine receptor activity. However, structural information about homo- and heterodimers formed by chemokine receptors and their interplay with cholesterol is limited. Here, we report homo- and heterodimer configurations of the chemokine receptors CXCR4, CCR5, and CCR2 at atomistic detail, as obtained from thousands of molecular dynamics simulations. The observed homodimerization patterns were similar for the closely related CC chemokine receptors, yet they differed significantly between the CC receptors and CXCR4. Despite their high sequence identity, cholesterol modulated the CC homodimer interfaces in a subtype-specific manner. Chemokine receptor heterodimers display distinct dimerization patterns for CXCR4/CCR5 and CXCR4/CCR2. Furthermore, associations between CXCR4 and CCR5 reveal an increased cholesterol-sensitivity as compared to CXCR4/CCR2 heterodimerization patterns. This work provides a first comprehensive structural overview over the complex interaction network between chemokine receptors and indicates how heterodimerization and the interaction with the membrane environment diversifies the function of closely related GPCRs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chemokines / metabolism
  • Cholesterol / metabolism
  • Computer Simulation
  • Dimerization
  • Humans
  • Molecular Dynamics Simulation
  • Receptors, CCR2 / chemistry
  • Receptors, CCR2 / metabolism
  • Receptors, CCR2 / ultrastructure
  • Receptors, CCR5 / chemistry
  • Receptors, CCR5 / metabolism
  • Receptors, CCR5 / ultrastructure
  • Receptors, CXCR4 / chemistry
  • Receptors, CXCR4 / metabolism
  • Receptors, CXCR4 / ultrastructure
  • Receptors, Chemokine / chemistry*
  • Receptors, Chemokine / genetics*
  • Receptors, G-Protein-Coupled / genetics*
  • Signal Transduction

Substances

  • Chemokines
  • Receptors, CCR2
  • Receptors, CCR5
  • Receptors, CXCR4
  • Receptors, Chemokine
  • Receptors, G-Protein-Coupled
  • Cholesterol

Grants and funding

This work was supported by the German Science Foundation (DFG; http://www.dfg.de) within the Research Training Group 1962 - Dynamic Interactions at Biological Membranes and the Department of Biology at the Friedrich-Alexander University of Erlangen-Nürnberg (http://www.biologie.nat.fau.de). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.