Asymmetric conformational changes in a GPCR dimer controlled by G-proteins

作者：Damian Marjorie; Martin Aimee; Mesnier Danielle; Pin Jean Philippe; Baneres Jean Louis^*

来源：The EMBO Journal, 2006, 25(24): 5693-5702.

DOI：10.1038/sj.emboj.7601449

• activation
• asymmetry
• dimer
• GPCR
• G-protein

G-protein-coupled receptors (GPCRs) are key players in cell communication. Although long considered as monomeric, it now appears that these heptahelical proteins can form homo- or heterodimers. Here, we analyzed the conformational changes in each subunit of a receptor dimer resulting from agonist binding to either one or both subunits by measuring the fluorescent properties of a leukotriene B4 receptor dimer with a single 5-hydroxytryptophanlabeled protomer. We show that a receptor dimer with only a single agonist-occupied subunit can trigger G-protein activation. We also show that the two subunits of the receptor dimer in the G-protein-coupled state differ in their conformation, even when both are liganded by the agonist. No such asymmetric conformational changes are observed in the absence of G-protein, indicating that the interaction of the G-protein with the receptor dimer brings specific constraints that prevent a symmetric functioning of this dimer. These data open new options for the differential signaling properties of GPCR dimers.

• 出版日期2006-12-13