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The N terminus of phosducin is involved in binding of βγ subunits of G protein

Xu, Jun and Wu, Dianqing and Slepak, Vladlen Z. and Simon, Melvin I. (1995) The N terminus of phosducin is involved in binding of βγ subunits of G protein. Proceedings of the National Academy of Sciences of the United States of America, 92 (6). pp. 2086-2090. ISSN 0027-8424. PMCID PMC42428. doi:10.1073/pnas.92.6.2086. https://resolver.caltech.edu/CaltechAUTHORS:20141208-145837046

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Abstract

Phosducin is a soluble phosphoprotein found in retinal photoreceptor cells and in the pineal gland. It binds to the βγ subunits of guanine nucleotide-binding proteins (G proteins) (Gβγ) and may regulate G-protein function. In this study, the ability of specific regions of phosducin to bind Gβγ was characterized. A series of deletion mutants were made in bovine phosducin. They were tested in cotransfection assays for their ability to inhibit Gβγ-mediated phospholipase C β_2 isoform activation. Overexpression of the N-terminal half of phosducin showed inhibition, whereas overexpression of the C-terminal half did not. The first 63 amino acid residues were required for inhibition. A tryptophan-to-valine substitution at residue 29, which is part of a well conserved 11-amino acid sequence, severely impaired phosducin inhibitory function. Glutathione S-transferase-phosducin fusion proteins were expressed in Escherichia coli to study phosducin-Gβγ interaction in vitro. The N-terminal 63-amino acid fragment was able to bind to Gβγ. In contrast, the C-terminal half failed to bind to Gβγ. The substitution mutants showed little or no binding. Furthermore, direct measurements of interaction between Gβγ and fragments of phosducin, using surface plasmon resonance technology, confirmed the assignment of binding activity to the 63-amino acid fragment and the importance of the tryptophan residue


Item Type:Article
Related URLs:
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http://dx.doi.org/10.1073/pnas.92.6.2086DOIArticle
http://www.ncbi.nlm.nih.gov/pmc/articles/pmc42428/PubMed CentralArticle
Alternate Title:The N terminus of phosducin is involved in binding of beta gamma subunits of G protein
Additional Information:© 1995 National Academy of Sciences. Contributed by Melvin I. Simon, December 7, 1994. We thank Dr. Rehwa Ho Lee for helpful discussions. This study was supported by National Institutes of Health Grant AG 12288 from the National Institute of Aging. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.
Funders:
Funding AgencyGrant Number
NIHAG 12288
Issue or Number:6
PubMed Central ID:PMC42428
DOI:10.1073/pnas.92.6.2086
Record Number:CaltechAUTHORS:20141208-145837046
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20141208-145837046
Official Citation:Xu, J., Wu, D., Slepak, V. Z., & Simon, M. I. (1995). The N terminus of phosducin is involved in binding of beta gamma subunits of G protein. Proceedings of the National Academy of Sciences, 92(6), 2086-2090.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:52480
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:09 Dec 2014 20:48
Last Modified:10 Nov 2021 19:41

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