PXD050824

PXD050824 is an original dataset announced via ProteomeXchange.

Title	Stabilization of Interdomain Interactions in G protein α Subunits as a Determinant of Gαi Subtype Signaling Specificity
Description	Highly homologous members of the Gαi family, Gαi1-3, have distinct tissue distributions and physiological functions, yet their biochemical and functional properties are very similar. We recently identified PDZ-RhoGEF (PRG) as a novel Gαi1 effector that is poorly activated by Gαi2. In a proteomic proximity labeling screen we observed a strong preference for Gαi1 relative to Gαi2 with respect to engagement of a broad range of potential targets. We investigated the mechanistic basis for this selectivity using PRG as a representative target. Substitution of either the helical domain (HD) from Gαi1 into Gαi2 or substitution of a single amino acid, A230 in Gαi2 with the corresponding D in Gαi1, largely rescues PRG activation and interactions with other potential Gαi targets. Molecular dynamics simulations combined with Bayesian network models revealed that in the GTP bound state, separation at the HD-Ras-like domain (RLD) interface is more pronounced in Gαi2 than Gαi1. Mutation of A230 to D in Gαi2 stabilizes HD-RLD interactions via ionic interactions with R145 in the HD which in turn modify the conformation of Switch III. These data support a model where D229 in Gαi1 interacts with R144 and stabilizes a network of interactions between HD and RLD to promote protein target recognition. The corresponding A230 in Gαi2 is unable to stabilize this network leading to an overall lower efficacy with respect to target interactions. This study reveals distinct mechanistic properties that could underly differential biological and physiological consequences of activation of Gαi1 or Gαi2 by GPCRs.
HostingRepository	PRIDE
AnnounceDate	2024-03-25
AnnouncementXML	Submission_2024-03-25_05:29:25.912.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Alan Smrcka
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: 9606;
ModificationList	TMT6plex-126 reporter+balance reagent acylated residue; monohydroxylated residue; deamidated residue; iodoacetamide derivatized residue
Instrument	Orbitrap Fusion

Revision	Datetime	Status	ChangeLog Entry
0	2024-03-20 12:02:40	ID requested
⏵ 1	2024-03-25 05:29:26	announced

10.1101/2023.06.07.544153;

Wei W, Smrcka AV, 2-Adrenergic Receptors Inhibit Subcellular Phospholipase C-Dependent Cardiac Hypertrophic Signaling. bioRxiv, ():(2023) [pubmed]

submitter keyword: Heterotrimeric G protein, Proximity labeling, mass spectrometry, structure., G protein-coupled receptor, effector coupling, Rho GEF, Domain interactions, alpha subunits

Alan V.
contact affiliation	Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI
contact email	avsmrcka@umich.edu
lab head
Alan Smrcka
contact affiliation	University of Michigan
contact email	avsmrcka@umich.edu
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD050824
     1. Label: PRIDE project
     2. Name: Stabilization of Interdomain Interactions in G protein α Subunits as a Determinant of Gαi Subtype Signaling Specificity