Influence of Physiologic and Environmental Factors on the Role of Regulator of G Protein Signaling 2 (RGS2) in Vascular Remodeling During Pregnancy

ABSTRACT AGS3, a receptor-independent activator of G-protein signaling, is involved in unexpected functional diversity for G-protein signaling systems. AGS3 has seven tetratricopeptide (TPR) motifs upstream of four G-protein regulatory (GPR) motifs that serve as docking sites for Giα-GDP. The positioning of AGS3 within the cell and the intramolecular dynamics between different domains of the proteins are likely key determinants of their ability to influence G-protein signaling. We report that AGS3 enters into the aggresome pathway and that distribution of the protein is regulated by the AGS3 binding partners Giα and mammalian Inscuteable (mInsc). Giα rescues AGS3 from the aggresome, whereas mInsc augments the aggresome-like distribution of AGS3. The distribution of AGS3 to the aggresome is dependent upon the TPR domain, and it is accelerated by disruption of the TPR organizational structure or introduction of a nonsynonymous single-nucleotide polymorphism. These data present AGS3, G-proteins, and mInsc as candidate proteins involved in regulating cellular stress associated with protein-processing pathologies.

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The Role of Inhibitory G Proteins and Regulators of G Protein Signaling in the in vivo Control of Heart Rate and Predisposition to Cardiac Arrhythmias

Frontiers in Physiology ◽

10.3389/fphys.2012.00096 ◽

2012 ◽

Vol 3 ◽

Cited By ~ 9

Author(s):

Richard Ang ◽

Aaisha Opel ◽

Andrew Tinker

Keyword(s):

Heart Rate ◽

G Protein ◽

G Proteins ◽

Cardiac Arrhythmias ◽

G Protein Signaling ◽

Protein Signaling

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Role of Molecular Chaperones in G Protein β5/Regulator of G Protein Signaling Dimer Assembly and G Protein βγ Dimer Specificity

Journal of Biological Chemistry ◽

10.1074/jbc.m900800200 ◽

2009 ◽

Vol 284 (24) ◽

pp. 16386-16399 ◽

Cited By ~ 19

Author(s):

Alyson C. Howlett ◽

Amy J. Gray ◽

Jesse M. Hunter ◽

Barry M. Willardson

Keyword(s):

G Protein ◽

Molecular Chaperones ◽

Vital Role ◽

G Protein Signaling ◽

Protein Signaling ◽

General Role ◽

The Many ◽

The Individual ◽

Dependent Mechanism

The G protein βγ subunit dimer (Gβγ) and the Gβ5/regulator of G protein signaling (RGS) dimer play fundamental roles in propagating and regulating G protein pathways, respectively. How these complexes form dimers when the individual subunits are unstable is a question that has remained unaddressed for many years. In the case of Gβγ, recent studies have shown that phosducin-like protein 1 (PhLP1) works as a co-chaperone with the cytosolic chaperonin complex (CCT) to fold Gβ and mediate its interaction with Gγ. However, it is not known what fraction of the many Gβγ combinations is assembled this way or whether chaperones influence the specificity of Gβγ dimer formation. Moreover, the mechanism of Gβ5-RGS assembly has yet to be assessed experimentally. The current study was undertaken to directly address these issues. The data show that PhLP1 plays a vital role in the assembly of Gγ2 with all four Gβ1–4 subunits and in the assembly of Gβ2 with all twelve Gγ subunits, without affecting the specificity of the Gβγ interactions. The results also show that Gβ5-RGS7 assembly is dependent on CCT and PhLP1, but the apparent mechanism is different from that of Gβγ. PhLP1 seems to stabilize the interaction of Gβ5 with CCT until Gβ5 is folded, after which it is released to allow Gβ5 to interact with RGS7. These findings point to a general role for PhLP1 in the assembly of all Gβγ combinations and suggest a CCT-dependent mechanism for Gβ5-RGS7 assembly that utilizes the co-chaperone activity of PhLP1 in a unique way.

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