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Preassembled GPCR signaling complexes mediate distinct cellular responses to ultralow ligand concentrations

Civciristov, Srgjan; Ellisdon, Andrew M.; Suderman, Ryan; Pon, Cindy K.; Evans, Bronwyn A.; Kleifeld, Oded; Charlton, Steven J.; Hlavacek, William S.; Canals, Meritxell; Halls, Michelle L.


Srgjan Civciristov

Andrew M. Ellisdon

Ryan Suderman

Cindy K. Pon

Bronwyn A. Evans

Oded Kleifeld

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Professor of Molecular Pharmacology and Drug Discovery

William S. Hlavacek

Michelle L. Halls


G protein–coupled receptors (GPCRs) are the largest class of cell surface signaling proteins, participate in nearly all physiological processes, and are the targets of 30% of marketed drugs. Typically, nanomolar to micromolar concentrations of ligand are used to activate GPCRs in experimental systems. We detected GPCR responses to a wide range of ligand concentrations, from attomolar to millimolar, by measuring GPCR-stimulated production of cyclic adenosine monophosphate (cAMP) with high spatial and temporal resolution. Mathematical modeling showed that femtomolar concentrations of ligand activated, on average, 40% of the cells in a population provided that a cell was activated by one to two binding events. Furthermore, activation of the endogenous β2-adrenergic receptor (β2AR) and muscarinic acetylcholine M3 receptor (M3R) by femtomolar concentrations of ligand in cell lines and human cardiac fibroblasts caused sustained increases in nuclear translocation of extracellular signal–regulated kinase (ERK) and cytosolic protein kinase C (PKC) activity, respectively. These responses were spatially and temporally distinct from those that occurred in response to higher concentrations of ligand and resulted in a distinct cellular proteomic profile. This highly sensitive signaling depended on the GPCRs forming preassembled, higher-order signaling complexes at the plasma membrane. Recognizing that GPCRs respond to ultralow concentrations of neurotransmitters and hormones challenges established paradigms of drug action and provides a previously unappreciated aspect of GPCR activation that is quite distinct from that typically observed with higher ligand concentrations.


Civciristov, S., Ellisdon, A. M., Suderman, R., Pon, C. K., Evans, B. A., Kleifeld, O., …Halls, M. L. (2018). Preassembled GPCR signaling complexes mediate distinct cellular responses to ultralow ligand concentrations. Science Signaling, 11(551), Article eaan1188.

Journal Article Type Article
Acceptance Date Sep 12, 2018
Online Publication Date Oct 9, 2018
Publication Date Oct 9, 2018
Deposit Date Oct 31, 2018
Publicly Available Date Apr 10, 2019
Journal Science Signaling
Print ISSN 1945-0877
Electronic ISSN 1937-9145
Publisher American Association for the Advancement of Science
Peer Reviewed Peer Reviewed
Volume 11
Issue 551
Article Number eaan1188
Keywords Cell Biology; Biochemistry; Molecular Biology
Public URL
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