The β2-adrenergic receptor associates with CXCR4 multimers in human cancer cells

• 成果类型: Article
• 署名作者: Liang, Junyi; Seghiri, Mohamed; Singh, Pradeep Kumar; Seo, Hyeon Gyu; Lee, Ji Yeong; Jo, Yoonjung; Song, Yong Bhum; Park, Chulo; Zalicki, Piotr; Jeong, Jae- Yeon; Huh, Won-Ki; Caculitan, Nina G.; Smith, Adam W.
• 署名单位: Cleveland Clinic Foundation; University System of Ohio; University of Akron; Texas Tech University System; Texas Tech University; Seoul National University (SNU); Seoul National University (SNU)
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8872
• DOI: 10.1073/pnas.2304897121
• 发表日期: 2024-04-02
• 关键词: protein-coupled receptors; adrenergic-receptors; small-molecule; beta-arrestin; activation; spectroscopy; dimerization

摘要

While the existence and functional role of class C G- protein- coupled receptors (GPCR) dimers is well established, there is still a lack of consensus regarding class A and B GPCR multimerization. This lack of consensus is largely due to the inherent challenges of demonstrating the presence of multimeric receptor complexes in a physiologically relevant cellular context. The C- X- C motif chemokine receptor 4 (CXCR4) is a class A GPCR that is a promising target of anticancer therapy. Here, we investigated the potential of CXCR4 to form multimeric complexes with other GPCRs and characterized the relative size of the complexes in a live- cell environment. Using a bimolecular fluorescence complementation (BiFC) assay, we identified the beta 2 adrenergic receptor (beta 2AR) as an interaction partner. To investigate the molecular scale details of CXCR4-beta 2AR interactions, we used a time- resolved fluorescence spectroscopy method called pulsed- interleaved excitation fluorescence cross- correlation spectroscopy (PIE- FCCS). PIE- FCCS can resolve membrane protein density, diffusion, and multimerization state in live cells at physiological expression levels. We probed CXCR4 and beta 2AR homo- and heteromultimerization in model cell lines and found that CXCR4 assembles into multimeric complexes larger than dimers in MDA- MB- 231 human breast cancer cells and in HCC4006 human lung cancer cells. We also found that beta 2AR associates with CXCR4 multimers in MDA- MB- 231 and HCC4006 cells to a higher degree than in COS- 7 and CHO cells and in a ligand- dependent manner. These results suggest that CXCR4-beta 2AR heteromers are present in human cancer cells and that GPCR multimerization is significantly affected by the plasma membrane environment.