Dataset Information

The G?i protein subclass selectivity to the dopamine D₂ receptor is also decided by their location at the cell membrane.

ABSTRACT:

Background

G protein-coupled receptor (GPCR) signaling via heterotrimeric G proteins plays an important role in the cellular regulation of responses to external stimuli. Despite intensive structural research, the mechanism underlying the receptor-G protein coupling of closely related subtypes of G?i remains unclear. In addition to the structural changes of interacting proteins, the interactions between lipids and proteins seem to be crucial in GPCR-dependent cell signaling due to their functional organization in specific membrane domains. In previous works, we found that G?s and G?i₃ subunits prefer distinct types of membrane-anchor lipid domains that also modulate the G protein trimer localization. In the present study, we investigated the functional selectivity of dopamine D₂ long receptor isoform (D₂R) toward the G?i₁, G?i₂, and G?i₃ subunits, and analyzed whether the organization of G?i heterotrimers at the plasma membrane affects the signal transduction.

Methods

We characterized the lateral diffusion and the receptor-G protein spatial distribution in living cells using two assays: fluorescence recovery after photobleaching microscopy and fluorescence resonance energy transfer detected by fluorescence-lifetime imaging microscopy. Depending on distribution of data differences between G? subunits were investigated using parametric approach-unpaired T-test or nonparametric-Mann-Whitney U test.

Results

Despite the similarities between the examined subunits, the experiments conducted in the study revealed a significantly faster lateral diffusion of the G?i₂ subunit and the singular distribution of the G?i₁ subunit in the plasma membrane. The cell membrane partitioning of distinct G?i heterotrimers with dopamine receptor correlated very well with the efficiency of D₂R-mediated inhibition the formation of cAMP.

Conclusions

This study showed that even closely related subunits of G?i differ in their membrane-trafficking properties that impact on their signaling. The interactions between lipids and proteins seem to be crucial in GPCR-dependent cell signaling due to their functional organization in specific membrane domains, and should therefore be taken into account as one of the selectivity determinants of G protein coupling. Video abstract.

SUBMITTER: Polit A

PROVIDER: S-EPMC7731117 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature

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Publications

The Gαi protein subclass selectivity to the dopamine D<sub>2</sub> receptor is also decided by their location at the cell membrane.

Polit Agnieszka A Rysiewicz Beata B Mystek Paweł P Błasiak Ewa E Dziedzicka-Wasylewska Marta M

Cell communication and signaling : CCS 20201211 1

<h4>Background</h4>G protein-coupled receptor (GPCR) signaling via heterotrimeric G proteins plays an important role in the cellular regulation of responses to external stimuli. Despite intensive structural research, the mechanism underlying the receptor-G protein coupling of closely related subtypes of Gαi remains unclear. In addition to the structural changes of interacting proteins, the interactions between lipids and proteins seem to be crucial in GPCR-dependent cell signaling due to their f ...[more]

PMID: 33308256

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Project description:Functional selectivity (or biased agonism) is a property exhibited by some G protein-coupled receptor (GPCR) ligands, which results in the modulation of a subset of a receptor's signaling capabilities and more precise control over complex biological processes. The dopamine D2 receptor (D2R) exhibits pleiotropic responses to the biogenic amine dopamine (DA) to mediate complex central nervous system functions through activation of G proteins and β-arrestins. D2R is a prominent therapeutic target for psychological and neurological disorders in which DA biology is dysregulated and targeting D2R with functionally selective drugs could provide a means by which pharmacotherapies could be developed. However, factors that determine GPCR functional selectivity in vivo may be multiple with receptors, ligands and transducers contributing to the process. We have recently described a mutagenesis approach to engineer biased D2R mutants in which G protein-dependent ([Gprot]D2R) and β-arrestin-dependent signaling ([βarr]D2R) were successfully separated (Peterson, et al. PNAS, 2015). Here, permutations of these mutants were used to identify critical determinants of the D2R signaling complex that impart signaling bias in response to the natural or synthetic ligands. Critical residues identified in generating [Gprot]D2R and [βarr]D2R conferred control of partial agonism at G protein and/or β-arrestin activity. Another set of mutations that result in G protein bias was identified that demonstrated that full agonists can impart unique activation patterns, and provided further credence to the concept of ligand texture. Finally, the contributions and interplay between different transducers indicated that G proteins are not aberrantly activated, and that receptor kinase and β-arrestin activities are inextricably linked. These data provide a thorough elucidation of the feasibility and malleability of D2R functional selectivity and point to means by which novel in vivo therapies could be modeled.

Dataset Information

The G?i protein subclass selectivity to the dopamine D₂ receptor is also decided by their location at the cell membrane.

Background

Methods

Results

Conclusions

Publications

The Gαi protein subclass selectivity to the dopamine D<sub>2</sub> receptor is also decided by their location at the cell membrane.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

The G?i protein subclass selectivity to the dopamine D2 receptor is also decided by their location at the cell membrane.

Background

Methods

Results

Conclusions

Publications

The Gαi protein subclass selectivity to the dopamine D<sub>2</sub> receptor is also decided by their location at the cell membrane.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

The G?i protein subclass selectivity to the dopamine D₂ receptor is also decided by their location at the cell membrane.