Activation of transducin guanosine triphosphatase by two proteins of the RGS family

Elina R. Nekrasova, David M. Berman, Richard R. Rustandi, Heidi E. Hamm, Alfred G. Gilman, Vadim Y. Arshavsky

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

RGS proteins (regulators of G protein signaling) constitute a newly appreciated group of negative regulators of G protein signaling. Several members of this group stimulate the guanosine triphosphatase (GTPase) activity of various G protein α-subunits, including the photoreceptor G protein, transducin. In photoreceptor cells transducin GTPase is known to be substantially accelerated by the coordinated action of the γ-subunit of its effector enzyme, cGMP phosphodiesterase (PDE(γ)), and another yet unidentified membrane-associated protein factor. Here we test the possibility that this factor belongs to the RGS family of GTPase stimulators. We report a detailed kinetic analysis of transducin GTPase activation by two members of the RGS family, RGS4 and Gα interacting protein (GAIP). RGS4, being at least 5-fold more potent than GAIP, stimulates the rate of transducin GTPase by 2 orders of magnitude. Neither RGS4 nor GAIP requires PDE(γ) for activating transducin. Rather, PDE(γ) causes a partial reversal of transducin GTPase activation by RGS proteins. The effect of PDE(γ) is based on a decreased apparent affinity of RGS for the α-subunit of transducin. Our observations indicate that GTPase activity of transducin can be activated by at least two distinct mechanisms, one based on the action of RGS proteins alone and another involving the cooperative action of the effector enzyme and another protein.

Original languageEnglish (US)
Pages (from-to)7638-7643
Number of pages6
JournalBiochemistry
Volume36
Issue number25
DOIs
StatePublished - Jun 24 1997

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RGS Proteins
Transducin
Guanosine
Chemical activation
Phosphoric Diester Hydrolases
GTP-Binding Protein Regulators
GTP-Binding Proteins
Proteins
Photoreceptor Cells
Protein Subunits
Enzymes
Membrane Proteins
Kinetics

ASJC Scopus subject areas

  • Biochemistry

Cite this

Nekrasova, E. R., Berman, D. M., Rustandi, R. R., Hamm, H. E., Gilman, A. G., & Arshavsky, V. Y. (1997). Activation of transducin guanosine triphosphatase by two proteins of the RGS family. Biochemistry, 36(25), 7638-7643. https://doi.org/10.1021/bi970427r

Activation of transducin guanosine triphosphatase by two proteins of the RGS family. / Nekrasova, Elina R.; Berman, David M.; Rustandi, Richard R.; Hamm, Heidi E.; Gilman, Alfred G.; Arshavsky, Vadim Y.

In: Biochemistry, Vol. 36, No. 25, 24.06.1997, p. 7638-7643.

Research output: Contribution to journalArticle

Nekrasova, ER, Berman, DM, Rustandi, RR, Hamm, HE, Gilman, AG & Arshavsky, VY 1997, 'Activation of transducin guanosine triphosphatase by two proteins of the RGS family', Biochemistry, vol. 36, no. 25, pp. 7638-7643. https://doi.org/10.1021/bi970427r
Nekrasova ER, Berman DM, Rustandi RR, Hamm HE, Gilman AG, Arshavsky VY. Activation of transducin guanosine triphosphatase by two proteins of the RGS family. Biochemistry. 1997 Jun 24;36(25):7638-7643. https://doi.org/10.1021/bi970427r
Nekrasova, Elina R. ; Berman, David M. ; Rustandi, Richard R. ; Hamm, Heidi E. ; Gilman, Alfred G. ; Arshavsky, Vadim Y. / Activation of transducin guanosine triphosphatase by two proteins of the RGS family. In: Biochemistry. 1997 ; Vol. 36, No. 25. pp. 7638-7643.
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