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XB-ART-47914
PLoS One 2013 Sep 03;89:e74354. doi: 10.1371/journal.pone.0074354.
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Voltage affects the dissociation rate constant of the m2 muscarinic receptor.

Ben Chaim Y , Bochnik S , Parnas I , Parnas H .


Abstract
G-protein coupled receptors (GPCRs) comprise the largest protein family and mediate the vast majority of signal transduction processes in the body. Until recently GPCRs were not considered to be voltage dependent. Newly it was shown for several GPCRs that the first step in GPCR activation, the binding of agonist to the receptor, is voltage sensitive: Voltage shifts the receptor between two states that differ in their binding affinity. Here we show that this shift involves the rate constant of dissociation. We used the m2 muscarinic receptor (m2R) a prototypical GPCR and measured directly the dissociation of [(3)H]ACh from m2R expressed Xenopus oocytes. We show, for the first time, that the voltage dependent change in affinity is implemented by voltage shifting the receptor between two states that differ in their rate constant of dissociation. Furthermore, we provide evidence that suggest that the above shift is achieved by voltage regulating the coupling of the GPCR to its G protein.

PubMed ID: 24019965
PMC ID: PMC3760861
Article link: PLoS One


Species referenced: Xenopus
Genes referenced: gprc6a kcnj3


Article Images: [+] show captions
References [+] :
Ben-Chaim, Movement of 'gating charge' is coupled to ligand binding in a G-protein-coupled receptor. 2006, Pubmed, Xenbase