Document Detail


Diffusion and light-dependent compartmentalization of transducin.
MedLine Citation:
PMID:  21044685     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Diffusion and light-dependent compartmentalization of transducin are essential for phototransduction and light adaptation of rod photoreceptors. Here, transgenic Xenopus laevis models were designed to probe the roles of transducin/rhodopsin interactions and lipid modifications in transducin compartmentalization, membrane mobility, and light-induced translocation. Localization and diffusion of EGFP-fused rod transducin-α subunit (Gα(t1)), mutant Gα(t1) that is predicted to be N-acylated and S-palmitoylated (Gα(t1)A3C), and mutant Gα(t1) uncoupled from light-activated rhodopsin (Gα(t1)-Ctα(s)), were examined by EGFP-fluorescence imaging and fluorescence recovery after photobleaching (FRAP). Similar to Gα(t1), Gα(t1)A3C and Gα(t1)-Ctα(s) were correctly targeted to the rod outer segments in the dark, however the light-dependent translocation of both mutants was markedly impaired. Our analysis revealed a moderate acceleration of the lateral diffusion for the activated Gα(t1) consistent with the diffusion of the separated Gα(t1)GTP and Gβ(1)γ(1) on the membrane surface. Unexpectedly, the kinetics of longitudinal diffusion were comparable for Gα(t1)GTP with a single lipid anchor and heterotrimeric Gα(t1)β(1)γ(1) or Gα(t1)-Ctα(s)β(1)γ(1) with two lipid modifications. This contrasted the lack of the longitudinal diffusion of the Gα(t1)A3C mutant apparently caused by its stable two lipid attachment to the membrane and suggests the existence of a mechanism that facilitates axial diffusion of Gα(t1)β(1)γ(1).
Authors:
Vasily Kerov; Nikolai O Artemyev
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2010-10-31
Journal Detail:
Title:  Molecular and cellular neurosciences     Volume:  46     ISSN:  1095-9327     ISO Abbreviation:  Mol. Cell. Neurosci.     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2011-01-10     Completed Date:  2011-07-05     Revised Date:  2012-01-04    
Medline Journal Info:
Nlm Unique ID:  9100095     Medline TA:  Mol Cell Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  340-6     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier Inc. All rights reserved.
Affiliation:
Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Animals, Genetically Modified
Diffusion
Fluorescence Recovery After Photobleaching
Light*
Protein Subunits / genetics,  metabolism
Protein Transport
Recombinant Fusion Proteins / genetics,  metabolism
Retinal Rod Photoreceptor Cells / cytology,  metabolism*
Rhodopsin / metabolism
Transducin / genetics,  metabolism*
Xenopus laevis
Grant Support
ID/Acronym/Agency:
R01 EY-12682/EY/NEI NIH HHS; R01 EY012682-12/EY/NEI NIH HHS
Chemical
Reg. No./Substance:
0/Protein Subunits; 0/Recombinant Fusion Proteins; 9009-81-8/Rhodopsin; EC 3.6.1.-/Transducin

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