Assembly of high order Gaq-effector complexes with RGS proteins

Aruna Shankaranarayanan, David Thal, Valerie M Tesmer, David L Roman, Richard Neubig, Tohru Kozasa, John Joseph Grubb Tesmer

Research output: Contribution to journalArticleResearchpeer-review

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Abstract

Transmembrane signaling through Gaq-coupled receptors is linked to physiological processes such as cardiovascular development and smooth muscle function. Recent crystallographic studies have shown how Gaq interacts with two activation-dependent targets, p63RhoGEF and G protein-coupled receptor kinase 2 (GRK2). These proteins bind to the effector-binding site of Gaq in a manner that does not appear to physically overlap with the site on Gaq bound by regulator of G-protein signaling (RGS) proteins, which function as GTPase-activating proteins (GAPs). Herein we confirm the formation of RGS-Gaq- GRK2/p63RhoGEF ternary complexes using flow cytometry protein interaction and GAP assays. RGS2 and, to a lesser extent, RGS4 are negative allosteric modulators of Gaq binding to either p63RhoGEF or GRK2. Conversely, GRK2 enhances the GAP activity of RGS4 but has little effect on that of RGS2. Similar but smaller magnitude responses are induced by p63RhoGEF. The fact that GRK2 and p63RhoGEF respond similarly to these RGS proteins supports the hypothesis that GRK2 is a bona fide Gaq effector. The results also suggest that signal transduction pathways initiated by GRK2, such as the phosphorylation of G protein-coupled receptors, and by p63RhoGEF, such as the activation of gene transcription, can be regulated by RGS proteins via both allosteric and GAP mechanisms.
Original languageEnglish
Pages (from-to)34923 - 34934
Number of pages12
JournalJournal of Biological Chemistry
Volume283
Issue number50
DOIs
Publication statusPublished - 2008
Externally publishedYes

Cite this

Shankaranarayanan, A., Thal, D., Tesmer, V. M., Roman, D. L., Neubig, R., Kozasa, T., & Tesmer, J. J. G. (2008). Assembly of high order Gaq-effector complexes with RGS proteins. Journal of Biological Chemistry, 283(50), 34923 - 34934. https://doi.org/10.1074/jbc.M805860200
Shankaranarayanan, Aruna ; Thal, David ; Tesmer, Valerie M ; Roman, David L ; Neubig, Richard ; Kozasa, Tohru ; Tesmer, John Joseph Grubb. / Assembly of high order Gaq-effector complexes with RGS proteins. In: Journal of Biological Chemistry. 2008 ; Vol. 283, No. 50. pp. 34923 - 34934.
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Shankaranarayanan, A, Thal, D, Tesmer, VM, Roman, DL, Neubig, R, Kozasa, T & Tesmer, JJG 2008, 'Assembly of high order Gaq-effector complexes with RGS proteins', Journal of Biological Chemistry, vol. 283, no. 50, pp. 34923 - 34934. https://doi.org/10.1074/jbc.M805860200

Assembly of high order Gaq-effector complexes with RGS proteins. / Shankaranarayanan, Aruna; Thal, David; Tesmer, Valerie M; Roman, David L; Neubig, Richard; Kozasa, Tohru; Tesmer, John Joseph Grubb.

In: Journal of Biological Chemistry, Vol. 283, No. 50, 2008, p. 34923 - 34934.

Research output: Contribution to journalArticleResearchpeer-review

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T1 - Assembly of high order Gaq-effector complexes with RGS proteins

AU - Shankaranarayanan, Aruna

AU - Thal, David

AU - Tesmer, Valerie M

AU - Roman, David L

AU - Neubig, Richard

AU - Kozasa, Tohru

AU - Tesmer, John Joseph Grubb

PY - 2008

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N2 - Transmembrane signaling through Gaq-coupled receptors is linked to physiological processes such as cardiovascular development and smooth muscle function. Recent crystallographic studies have shown how Gaq interacts with two activation-dependent targets, p63RhoGEF and G protein-coupled receptor kinase 2 (GRK2). These proteins bind to the effector-binding site of Gaq in a manner that does not appear to physically overlap with the site on Gaq bound by regulator of G-protein signaling (RGS) proteins, which function as GTPase-activating proteins (GAPs). Herein we confirm the formation of RGS-Gaq- GRK2/p63RhoGEF ternary complexes using flow cytometry protein interaction and GAP assays. RGS2 and, to a lesser extent, RGS4 are negative allosteric modulators of Gaq binding to either p63RhoGEF or GRK2. Conversely, GRK2 enhances the GAP activity of RGS4 but has little effect on that of RGS2. Similar but smaller magnitude responses are induced by p63RhoGEF. The fact that GRK2 and p63RhoGEF respond similarly to these RGS proteins supports the hypothesis that GRK2 is a bona fide Gaq effector. The results also suggest that signal transduction pathways initiated by GRK2, such as the phosphorylation of G protein-coupled receptors, and by p63RhoGEF, such as the activation of gene transcription, can be regulated by RGS proteins via both allosteric and GAP mechanisms.

AB - Transmembrane signaling through Gaq-coupled receptors is linked to physiological processes such as cardiovascular development and smooth muscle function. Recent crystallographic studies have shown how Gaq interacts with two activation-dependent targets, p63RhoGEF and G protein-coupled receptor kinase 2 (GRK2). These proteins bind to the effector-binding site of Gaq in a manner that does not appear to physically overlap with the site on Gaq bound by regulator of G-protein signaling (RGS) proteins, which function as GTPase-activating proteins (GAPs). Herein we confirm the formation of RGS-Gaq- GRK2/p63RhoGEF ternary complexes using flow cytometry protein interaction and GAP assays. RGS2 and, to a lesser extent, RGS4 are negative allosteric modulators of Gaq binding to either p63RhoGEF or GRK2. Conversely, GRK2 enhances the GAP activity of RGS4 but has little effect on that of RGS2. Similar but smaller magnitude responses are induced by p63RhoGEF. The fact that GRK2 and p63RhoGEF respond similarly to these RGS proteins supports the hypothesis that GRK2 is a bona fide Gaq effector. The results also suggest that signal transduction pathways initiated by GRK2, such as the phosphorylation of G protein-coupled receptors, and by p63RhoGEF, such as the activation of gene transcription, can be regulated by RGS proteins via both allosteric and GAP mechanisms.

U2 - 10.1074/jbc.M805860200

DO - 10.1074/jbc.M805860200

M3 - Article

VL - 283

SP - 34923

EP - 34934

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 1083-351X

IS - 50

ER -

Shankaranarayanan A, Thal D, Tesmer VM, Roman DL, Neubig R, Kozasa T et al. Assembly of high order Gaq-effector complexes with RGS proteins. Journal of Biological Chemistry. 2008;283(50):34923 - 34934. https://doi.org/10.1074/jbc.M805860200