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PMID: 22329346 Published · ppublish English Journal Article Research Support, N.I.H., Extramural

Myristoylation exerts direct and allosteric effects on Gα conformation and dynamics in solution.

Biochemistry ·Vol. 51 ·No. 9 ·2012-03-06 ·Pages 1911-24

Preininger AM, Kaya AI, Gilbert JA, Busenlehner LS, Armstrong RN, Hamm HE

Abstract

Coupling of heterotrimeric G proteins to activated G protein-coupled receptors results in nucleotide exchange on the Gα subunit, which in turn decreases its affinity for both Gβγ and activated receptors. N-Terminal myristoylation of Gα subunits aids in membrane localization of inactive G proteins. Despite the presence of the covalently attached myristoyl group, Gα proteins are highly soluble after GTP binding. This study investigated factors facilitating the solubility of the activated, myristoylated protein. In doing so, we also identified myristoylation-dependent differences in regions of Gα known to play important roles in interactions with receptors, effectors, and nucleotide binding. Amide hydrogen-deuterium exchange and site-directed fluorescence of activated proteins revealed a solvent-protected amino terminus that was enhanced by myristoylation. Furthermore, fluorescence quenching confirmed that the myristoylated amino terminus is in proximity to the Switch II region in the activated protein. Myristoylation also stabilized the interaction between the guanine ring and the base of the α5 helix that contacts the bound nucleotide. The allosteric effects of myristoylation on protein structure, function, and localization indicate that the myristoylated amino terminus of Gα(i) functions as a myristoyl switch, with implications for myristoylation in the stabilization of nucleotide binding and in the spatial regulation of G protein signaling.

MeSH Terms
Allosteric Regulation Animals Deuterium Exchange Measurement GTP-Binding Protein alpha Subunits, Gi-Go/chemistry,metabolism Models, Molecular Myristic Acid/metabolism Protein Conformation Rats Signal Transduction Solutions
Chemicals
Solutions Myristic Acid GTP-Binding Protein alpha Subunits, Gi-Go
Authors & Affiliations
6 authors, click to expand affiliations / ORCID
Preininger Anita M
Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States.
Kaya Ali I
Gilbert James A
Busenlehner Laura S
Armstrong Richard N
Hamm Heidi E
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Article Info
Journal
Biochemistry
Abbr.
Biochemistry
ISSN
1520-4995
DOI
10.1021/bi201472c
Published
2012-03-06
Epub
2012-00-22
Pages
1911-24
Language
English
Region
United States
NLM ID
0370623
PMCID
PMC3312377
Subset
IM
Grants
NCRR NIH HHS · TL1 RR024978 · United States
NCRR NIH HHS · KL2 RR024977 · United States
NIGMS NIH HHS · R01 GM030910 · United States
NEI NIH HHS · R01 EY006062 · United States
NCRR NIH HHS · UL1 RR024975-01 · United States
NEI NIH HHS · R01 EY06062 · United States
NIGMS NIH HHS · R01 GM030910-29 · United States
NEI NIH HHS · R01 EY006062-26 · United States
NCRR NIH HHS · UL1 RR024975 · United States
External Links
PubMed source DOI: 10.1021/bi201472c PMC Full Text View journal details
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