Calcium and light adaptation in retinal rods and cones

Nakatani, Keigo; Yau, King Wai

doi:10.1038/334069a0

Cited by 365 publications

(282 citation statements)

References 20 publications

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“…Ca ~+ entry in the dark provides negative feedback control of cGMP synthesis (LoUey and Racz, 1982;Pepe, Panfoli, and Cugnoli, 1986;Hodgkin and Nunn, 1988;Koch and Stryer, 1988;Dizhoor, Ray, Kumar, Niemi, Spencer, Brolley, Walsh, Philipov, Hurley, and Stryer, 1991). A light-induced drop in internal Ca 2+ concentration (Yau and Nakatani, 1985;McNaughton, Cervetto, and Nunn, 1986) is important for the recovery of the light response and for light adaptation (Matthews, Murphy, Fain, and Lamb, 1988;Nakatani and Yau, 1988b).…”

Section: Introductionmentioning

confidence: 99%

Interactions between divalent cations and the gating machinery of cyclic GMP-activated channels in salamander retinal rods.

Karpen

Brown

Stryer

et al. 1993

The Journal of General Physiology

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The effects of divalent cations on the gating of the cGMP-activated channel, and the effects of gating on the movement of divalent cations in and out of the channel's pore were studied by recording macroscopic currents in excised membrane patches from salamander retinal rods. The fractional block of cGMPactivated Na + currents by internal and external Mg 2+ as well as internal Ca ~+ was nearly independent ofcGMP concentration. This indicates that Mg 2÷ and Ca ~÷ bind with similar affinity to open and closed states of the channel. In contrast, the efficiency of block by internal Cd 2÷ or Zn 2÷ increased in proportion to the fraction of open channels, indicating that these ions preferentially occupy open channels. The kinetics of block by internal Ni 2+, which competes with Mg z÷ but blocks more slowly, were found to be unaffected by the fraction of channels open. External Ni z÷, however, blocked and unblocked much more rapidly when channels were mostly open. This suggests that within the pore a gate is located between the binding site(s) for ions and the extraceUular mouth of the channel. Micromolar concentrations of the transition metal divalent cations Ni 2÷, Cd 2+, Zn ~+, and Mn 2÷ applied to the cytoplasmic surface of a patch potentiated the response to subsaturating concentrations of cGMP without affecting the maximum current induced by saturating cGMP. The concentration of cGMP that opened half the channels was often lowered by a factor of three or more. Potentiation persisted after the experimental chamber was washed with divalent-free solution and fresh cGMP was applied, indicating that it does not result from an interaction between divalent cations and cGMP in solution; 1 mM EDTA or isotonic MgCl~ reversed potentiation. Voltage-jump experiments suggest that potentiation results from an increase in the rate of cGMP binding. Lowering the ionic strength of the bathing solution enhanced potentiation, suggesting that it involves electrostatic interactions. The strong electrostatic effect on cGMP binding and absence of effect on ion permeation through open channels implies that the cGMP binding sites on the channel are well separated from the permeation pathway.Address reprint requests to Dr.

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Section: Introductionmentioning

confidence: 99%

Interactions between divalent cations and the gating machinery of cyclic GMP-activated channels in salamander retinal rods.

Karpen

Brown

Stryer

et al. 1993

The Journal of General Physiology

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“…Adaptation in both rods and cones is mediated by light-induced decline in their outer segment free calcium ([Ca 2ϩ ] i ) (4,5). In the dark, the influx of calcium through cGMP-gated transduction channels is matched by its extrusion via rod-or cone-specific Na ϩ /(Ca 2ϩ , K ϩ ) exchangers (6).…”

mentioning

confidence: 99%

Regulation of Mammalian Cone Phototransduction by Recoverin and Rhodopsin Kinase

Sakurai

Chen

Khani

et al. 2015

Journal of Biological Chemistry

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Background: Calcium-mediated feedback to phototransduction is critical for modulating cone responses under different lighting conditions. Results: The calcium-binding protein recoverin potentiates dim light sensitivity, whereas increasing expression of its target, GRK1, delays response shutoff in cones. Conclusion: Recoverin and GRK1 levels modulate cone phototransduction. Significance: Cone pigment inactivation regulates cone responses in dim light but not in bright light.

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“…These modulations are attained by changes in the cytoplasmic Ca 2ϩ concentration (3,4). In the dark, the cytoplasmic Ca 2ϩ concentration in a rod is in a range of several hundred nanomolar (5,6).…”

mentioning

confidence: 99%

Amino Acid Residues of S-modulin Responsible for Interaction with Rhodopsin Kinase

Tachibanaki

Nanda

Sasaki

et al. 2000

Journal of Biological Chemistry

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S-modulin in frog or its bovine homologue, recoverin, is a 23-kDa EF-hand Ca 2؉ -binding protein found in rod photoreceptors. The Ca 2؉ -bound form of S-modulin binds to rhodopsin kinase (Rk) and inhibits its activity. Through this regulation, S-modulin is thought to modulate the light sensitivity of a rod. In the present study, we tried to identify the interaction site of the Ca 2؉ -bound form of S-modulin to Rk. First, we mapped roughly the interaction regions by using partial peptides of S-modulin. The result suggested that a specific region near the amino terminus is the interaction site of S-modulin. We then identified the essential amino acid residues in this region by using S-modulin mutant proteins: four amino acid residues (Phe 22 , Glu 26 , Phe 55 , and Thr 92 ) were suggested to interact with Rk. These residues are located in a small closed pocket in the Ca 2؉ -free, inactive form of S-modulin, but exposed to the surface of the molecule in the Ca 2؉ -bound, active form of S-modulin. Two additional amino acid residues (Tyr 108 and Arg 150 ) were found to be crucial for the Ca 2؉ -dependent conformational changes of S-modulin.

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Calcium and light adaptation in retinal rods and cones

Cited by 365 publications

References 20 publications

Interactions between divalent cations and the gating machinery of cyclic GMP-activated channels in salamander retinal rods.

Interactions between divalent cations and the gating machinery of cyclic GMP-activated channels in salamander retinal rods.

Regulation of Mammalian Cone Phototransduction by Recoverin and Rhodopsin Kinase

Amino Acid Residues of S-modulin Responsible for Interaction with Rhodopsin Kinase

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