Document Detail

Molecular properties of rhodopsin and rod function.
MedLine Citation:
PMID:  17194706     Owner:  NLM     Status:  MEDLINE    
Signal transduction in rod cells begins with photon absorption by rhodopsin and leads to the generation of an electrical response. The response profile is determined by the molecular properties of the phototransduction components. To examine how the molecular properties of rhodopsin correlate with the rod-response profile, we have generated a knock-in mouse with rhodopsin replaced by its E122Q mutant, which exhibits properties different from those of wild-type (WT) rhodopsin. Knock-in mouse rods with E122Q rhodopsin exhibited a photosensitivity about 70% of WT. Correspondingly, their single-photon response had an amplitude about 80% of WT, and a rate of decline from peak about 1.3 times of WT. The overall 30% lower photosensitivity of mutant rods can be explained by a lower pigment photosensitivity (0.9) and the smaller single-photon response (0.8). The slower decline of the response, however, did not correlate with the 10-fold shorter lifetime of the meta-II state of E122Q rhodopsin. This shorter lifetime became evident in the recovery phase of rod cells only when arrestin was absent. Simulation analysis of the photoresponse profile indicated that the slower decline and the smaller amplitude of the single-photon response can both be explained by the shift in the meta-I/meta-II equilibrium of E122Q rhodopsin toward meta-I. The difference in meta-III lifetime between WT and E122Q mutant became obvious in the recovery phase of the dark current after moderate photobleaching of rod cells. Thus, the present study clearly reveals how the molecular properties of rhodopsin affect the amplitude, shape, and kinetics of the rod response.
Hiroo Imai; Vladimir Kefalov; Keisuke Sakurai; Osamu Chisaka; Yoshiki Ueda; Akishi Onishi; Takefumi Morizumi; Yingbin Fu; Kazuhisa Ichikawa; Kei Nakatani; Yoshihito Honda; Jeannie Chen; King-Wai Yau; Yoshinori Shichida
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2006-12-28
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  282     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2007 Mar 
Date Detail:
Created Date:  2007-02-26     Completed Date:  2007-06-18     Revised Date:  2014-09-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  6677-84     Citation Subset:  IM    
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MeSH Terms
Mutation, Missense
Retinal Rod Photoreceptor Cells / physiology*
Rhodopsin / genetics
Vision, Ocular*
Grant Support
EY 06837/EY/NEI NIH HHS; R01 DC006904/DC/NIDCD NIH HHS; R01 DC006904-01/DC/NIDCD NIH HHS; R01 DC006904-02/DC/NIDCD NIH HHS; R01 DC006904-03/DC/NIDCD NIH HHS; R01 EY006837/EY/NEI NIH HHS; R01 EY006837-16A1/EY/NEI NIH HHS; R01 EY006837-17/EY/NEI NIH HHS; R01 EY006837-18/EY/NEI NIH HHS; R01 EY006837-19/EY/NEI NIH HHS; R01 EY006837-20A1/EY/NEI NIH HHS; R01 EY014596/EY/NEI NIH HHS; R01 EY014596-01/EY/NEI NIH HHS; R01 EY014596-02/EY/NEI NIH HHS; R01 EY014596-03/EY/NEI NIH HHS; R01 EY014596-04/EY/NEI NIH HHS; R01 EY014596-05/EY/NEI NIH HHS
Reg. No./Substance:
0/Arrestin; 9009-81-8/Rhodopsin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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