Journal article
Photoreceptor Phosphodiesterase: Interaction of Inhibitory γ Subunit and Cyclic GMP with Specific Binding Sites on Catalytic Subunits
Methods (San Diego, Calif.), Vol.14(1), pp.93-104
01/1998
DOI: 10.1006/meth.1997.0568
PMID: 9500861
Abstract
The photoreceptor phosphodiesterase (PDE6) is the central effector enzyme in the phototransduction cascade of photoreceptor cells. It is the only known PDE isoform the activity of which is regulated by interaction with a heterotrimeric G protein. The rod PDE6 holoenzyme is a tetrameric protein consisting of two large catalytic α and β subunits and two small γ subunits, which serve as potent inhibitors of PDE6. In dark-adapted photoreceptors, the γ subunits maintain PDE6 activity at a low level. When exposed to light the visual pigment rhodopsin activates the retinal G protein, transducin, leading to release of the inhibitory action of the γ subunits. In addition to the active sites where cGMP is hydrolyzed, the α and β catalytic subunits have high-affinity, noncatalytic cGMP binding sites. These noncatalytic sites do not directly regulate cGMP catalysis at the active site, but rather can modulate the affinity with which the γ subunits bind to the catalytic subunits. This article describes a number of experimental approaches that have recently been developed for studying the interactions between catalytic and inhibitory subunits of PDE6, as well as the dynamics of cGMP binding to and dissociation from the PDE6 noncatalytic sites.
Details
- Title: Subtitle
- Photoreceptor Phosphodiesterase: Interaction of Inhibitory γ Subunit and Cyclic GMP with Specific Binding Sites on Catalytic Subunits
- Creators
- Nikolai O Artemyev - Department of Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, 52242Vadim Y Arshavsky - Howe Laboratory of Ophthalmology, Harvard Medical School and Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, 02114Rick H Cote - Department of Biochemistry and Molecular Biology, University of New Hampshire, Durham, New Hampshire, 03824
- Resource Type
- Journal article
- Publication Details
- Methods (San Diego, Calif.), Vol.14(1), pp.93-104
- Publisher
- Elsevier Inc
- DOI
- 10.1006/meth.1997.0568
- PMID
- 9500861
- ISSN
- 1046-2023
- eISSN
- 1095-9130
- Language
- English
- Date published
- 01/1998
- Academic Unit
- Molecular Physiology and Biophysics; Iowa Neuroscience Institute; Ophthalmology and Visual Sciences
- Record Identifier
- 9984025572702771
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