A monomeric G protein-coupled receptor isolated in a high-density lipoprotein particle efficiently activates its G protein
Research output: Contribution to journal › Journal article › Research › peer-review
Standard
A monomeric G protein-coupled receptor isolated in a high-density lipoprotein particle efficiently activates its G protein. / Whorton, Matthew R; Bokoch, Michael P; Rasmussen, Søren Gøgsig Faarup; Huang, Bo; Zare, Richard N; Kobilka, Brian; Sunahara, Roger K.
In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 104, No. 18, 01.05.2007, p. 7682-7.Research output: Contribution to journal › Journal article › Research › peer-review
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - A monomeric G protein-coupled receptor isolated in a high-density lipoprotein particle efficiently activates its G protein
AU - Whorton, Matthew R
AU - Bokoch, Michael P
AU - Rasmussen, Søren Gøgsig Faarup
AU - Huang, Bo
AU - Zare, Richard N
AU - Kobilka, Brian
AU - Sunahara, Roger K
PY - 2007/5/1
Y1 - 2007/5/1
N2 - G protein-coupled receptors (GPCRs) respond to a diverse array of ligands, mediating cellular responses to hormones and neurotransmitters, as well as the senses of smell and taste. The structures of the GPCR rhodopsin and several G proteins have been determined by x-ray crystallography, yet the organization of the signaling complex between GPCRs and G proteins is poorly understood. The observations that some GPCRs are obligate heterodimers, and that many GPCRs form both homo- and heterodimers, has led to speculation that GPCR dimers may be required for efficient activation of G proteins. However, technical limitations have precluded a definitive analysis of G protein coupling to monomeric GPCRs in a biochemically defined and membrane-bound system. Here we demonstrate that a prototypical GPCR, the beta2-adrenergic receptor (beta2AR), can be incorporated into a reconstituted high-density lipoprotein (rHDL) phospholipid bilayer particle together with the stimulatory heterotrimeric G protein, Gs. Single-molecule fluorescence imaging and FRET analysis demonstrate that a single beta2AR is incorporated per rHDL particle. The monomeric beta2AR efficiently activates Gs and displays GTP-sensitive allosteric ligand-binding properties. These data suggest that a monomeric receptor in a lipid bilayer is the minimal functional unit necessary for signaling, and that the cooperativity of agonist binding is due to G protein association with a receptor monomer and not receptor oligomerization.
AB - G protein-coupled receptors (GPCRs) respond to a diverse array of ligands, mediating cellular responses to hormones and neurotransmitters, as well as the senses of smell and taste. The structures of the GPCR rhodopsin and several G proteins have been determined by x-ray crystallography, yet the organization of the signaling complex between GPCRs and G proteins is poorly understood. The observations that some GPCRs are obligate heterodimers, and that many GPCRs form both homo- and heterodimers, has led to speculation that GPCR dimers may be required for efficient activation of G proteins. However, technical limitations have precluded a definitive analysis of G protein coupling to monomeric GPCRs in a biochemically defined and membrane-bound system. Here we demonstrate that a prototypical GPCR, the beta2-adrenergic receptor (beta2AR), can be incorporated into a reconstituted high-density lipoprotein (rHDL) phospholipid bilayer particle together with the stimulatory heterotrimeric G protein, Gs. Single-molecule fluorescence imaging and FRET analysis demonstrate that a single beta2AR is incorporated per rHDL particle. The monomeric beta2AR efficiently activates Gs and displays GTP-sensitive allosteric ligand-binding properties. These data suggest that a monomeric receptor in a lipid bilayer is the minimal functional unit necessary for signaling, and that the cooperativity of agonist binding is due to G protein association with a receptor monomer and not receptor oligomerization.
KW - Animals
KW - Cattle
KW - Fluorescence Resonance Energy Transfer
KW - GTP-Binding Proteins
KW - Humans
KW - Lipoproteins, HDL
KW - Microscopy, Electron, Transmission
KW - Models, Molecular
KW - Protein Binding
KW - Protein Structure, Quaternary
KW - Receptors, Adrenergic, beta-2
U2 - 10.1073/pnas.0611448104
DO - 10.1073/pnas.0611448104
M3 - Journal article
C2 - 17452637
VL - 104
SP - 7682
EP - 7687
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 18
ER -
ID: 120588868