Dataset Information

Channel modulation and the mechanism of light adaptation in mouse rods.

ABSTRACT: Vertebrate photoreceptors are thought to adapt to light by a change in Ca(2+), which is postulated to mediate modulation of (1) excited rhodopsin (Rh*) by Ca(2+)-dependent binding of recoverin, (2) guanylyl cyclase activity via Ca(2+)-dependent GCAP proteins, and (3) cyclic nucleotide-gated channels by binding of Ca(2+)-calmodulin. Previous experiments genetically deleted recoverin and the GCAPs and showed that significant regulation of sensitivity survives removal of (1) and (2). We genetically deleted the channel Ca(2+)-calmodulin binding site in the mouse Mus musculus and found that removal of (3) alters response waveform, but removal of (3) or of (2) and (3) together still leaves much of adaptation intact. These experiments demonstrate that an important additional mechanism is required, which other experiments indicate may be regulation of phosphodiesterase 6 (PDE6). We therefore constructed a kinetic model in which light produces a Ca(2+)-mediated decrease in PDE6 decay rate, with the novel feature that both spontaneously activated and light-activated PDE6 are modulated. This model, together with Ca(2+)-dependent acceleration of guanylyl cyclase, can successfully account for changes in sensitivity and response waveform in background light.

SUBMITTER: Chen J

PROVIDER: S-EPMC3010974 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature

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Publications

Channel modulation and the mechanism of light adaptation in mouse rods.

Chen Jeannie J Woodruff Michael L ML Wang Tian T Concepcion Francis A FA Tranchina Daniel D Fain Gordon L GL

The Journal of neuroscience : the official journal of the Society for Neuroscience 20101201 48

Vertebrate photoreceptors are thought to adapt to light by a change in Ca(2+), which is postulated to mediate modulation of (1) excited rhodopsin (Rh*) by Ca(2+)-dependent binding of recoverin, (2) guanylyl cyclase activity via Ca(2+)-dependent GCAP proteins, and (3) cyclic nucleotide-gated channels by binding of Ca(2+)-calmodulin. Previous experiments genetically deleted recoverin and the GCAPs and showed that significant regulation of sensitivity survives removal of (1) and (2). We genetically ...[more]

PMID: 21123569

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Dataset Information

Channel modulation and the mechanism of light adaptation in mouse rods.

Publications

Channel modulation and the mechanism of light adaptation in mouse rods.

Similar Datasets

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