Dominant negative mutants of transducin-alpha that block activated receptor

Michael Natochin; Brandy Barren; Nikolai O Artemyev

doi:10.1021/bi060381e

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Dominant negative mutants of transducin-alpha that block activated receptor

Journal article

Open access

Peer reviewed

Dominant negative mutants of transducin-alpha that block activated receptor

Michael Natochin, Brandy Barren and Nikolai O Artemyev

Biochemistry (Easton), Vol.45(20), pp.6488-6494

05/23/2006

DOI: 10.1021/bi060381e

PMCID: PMC2525804

PMID: 16700559

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https://www.ncbi.nlm.nih.gov/pmc/articles/2525804View

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Abstract

Mutations counterpart to dominant negative RasSer17Asn in the alpha-subunits of heterotrimeric G-proteins are known to also produce dominant negative effects. The mechanism of these mutations remains poorly understood. Here, we examined the effects and mechanism of the Ser43Cys and Ser43Asn mutants of transducin-like chimeric Gtalpha* in the visual signaling system. Our analysis showed that both mutants have reduced affinity for GDP and are likely to exist in an empty-or partially occupied-pocket state. S43C and S43N retained the ability to interact with Gtbetagamma and, as heterotrimeric proteins, bind to photoexcited rhodopsin (R*). The interaction with R* is unproductive as the mutants failed to bind GTPgammaS and become activated. S43C and S43N inhibited R*-dependent activation of Gtalpha* and Gtalpha, apparently by blocking R*. Finally, both Gtalpha* mutants lacked interaction with the gamma-subunit of PDE6, an effector protein in phototransduction. These results indicate that the S43C and S43N mutants of Gtalpha* are dominant negative inhibitors that bind and block the activated receptor in a mechanism that parallels that of RasSer17Asn. Dominant negative mutants of Gtalpha sequestering R*, such as S43C and S43N, may become useful instruments in probing the mechanisms of visual dysfunctions caused by abnormal phototransduction signaling.

Mutation

Transducin - genetics

Phosphoric Diester Hydrolases - metabolism

Guanosine 5'-O-(3-Thiotriphosphate) - genetics

Pertussis Toxin - metabolism

Nucleotides - metabolism

Rhodopsin - metabolism

Trypsin - metabolism

Protein Subunits - metabolism

Guanosine 5'-O-(3-Thiotriphosphate) - metabolism

Rhodopsin - antagonists & inhibitors

Protein Binding

Transducin - metabolism

Cyclic Nucleotide Phosphodiesterases, Type 6

Adenosine Diphosphate - metabolism

Catalysis

Details

Title: Subtitle: Dominant negative mutants of transducin-alpha that block activated receptor
Creators: Michael Natochin - Department of Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
Brandy Barren
Nikolai O Artemyev
Resource Type: Journal article
Publication Details: Biochemistry (Easton), Vol.45(20), pp.6488-6494
DOI: 10.1021/bi060381e
PMID: 16700559
PMCID: PMC2525804
NLM abbreviation: Biochemistry
ISSN: 0006-2960
eISSN: 1520-4995
Publisher: United States
Grant note: R01 EY012682-09 / NEI NIH HHS R01 EY012682 / NEI NIH HHS EY12682 / NEI NIH HHS
Language: English
Date published: 05/23/2006
Academic Unit: Molecular Physiology and Biophysics; Iowa Neuroscience Institute; Ophthalmology and Visual Sciences
Record Identifier: 9984025421302771

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