Dataset Information

Stabilization of Interdomain Interactions in G protein α Subunits as a Determinant of Gαi Subtype Signaling Specificity

ABSTRACT: 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.

INSTRUMENT(S): Orbitrap Fusion

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Keratinocyte

SUBMITTER: Alan Smrcka

LAB HEAD: Alan V.

PROVIDER: PXD050824 | Pride | 2024-03-25

REPOSITORIES: Pride

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Dataset's files

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			Action	DRS
	PRF_F_2019_A_SMRC_274_48732_48742_1.raw	Raw
	PRF_F_2019_A_SMRC_274_48732_48742_1_8.msf	Msf
	PRF_F_2019_A_SMRC_274_48732_48742_2.raw	Raw
	PRF_F_2019_A_SMRC_274_48732_48742_3.raw	Raw
	PRF_F_2019_A_SMRC_274_48732_48742_4.raw	Raw

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Publications

Internalized β2-Adrenergic Receptors Inhibit Subcellular Phospholipase C-Dependent Cardiac Hypertrophic Signaling.

Wei Wenhui W Smrcka Alan V AV

bioRxiv : the preprint server for biology 20230609

Chronically elevated neurohumoral drive, and particularly elevated adrenergic tone leading to β-adrenergic receptor (β-AR) overstimulation in cardiac myocytes, is a key mechanism involved in the progression of heart failure. β1-AR and β2-ARs are the two major subtypes of β-ARs present in the human heart, however, they elicit different or even opposite effects on cardiac function and hypertrophy. For example, chronic activation of β1ARs drives detrimental cardiac remodeling while β2AR signaling i ...[more]

PMID: 37333278

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