Effect of bleached rhodopsin on signal amplification in rod visual receptors

Kahlert, M.; Pepperberg, David R.; Hofmann, Klaus Peter

doi:10.1038/345537a0

Cited by 81 publications

(29 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[22]), a regulation of rod sensitivity that appears to bypass the G-protein [23,24]. Whether a regulatory pathway exits, which originates from the light-dependent release of arrestin-bound inositol phosphates, remains to be investigated.…”

Section: Discussionmentioning

confidence: 99%

Binding of inositol phosphates to arrestin

et al. 1991

Self Cite

View full text Add to dashboard Cite

Arrcstin binds to phosphorylavzd rhodopsin in its light-activated form (melarhodopsin II), blocking thcrcby its interaction with the G-protein, mmsducin. In this study, WC show thal highly phosphorylatcd forms of inositol compete against the arrcslin-rhodopsin inlcraction. Competition curves and direct binding assays with free arrcslin consislcntly yield affinities in the micromolar range; for example, inositol 1.3.4.5-telrakisphospharc (InP,) and inosilol hcxakisphosphalc (InP, bind to arrcstin with dissociation constants of 12pM and 5 PM. respectively. Only a small control amount or inosilol phosphates is bound. when arrcstin interacts wilh phosphorylatcd rhodopsin.This argues for a release of bound inositol phosphates by imernclion with rhodopsin. Transducin, rhodopsin kinasc, or cyclic GMP phosphodicsterasc arc noi affected by inositol phosphates. These observations open a new way 10 purify arrcsiin and to inhibh its imcraction with rhodopsin. Their physiological significance dcscrvcs further inscsligalion.

show abstract

Section: Discussionmentioning

confidence: 99%

Binding of inositol phosphates to arrestin

et al. 1991

Self Cite

View full text Add to dashboard Cite

show abstract

“…Previous studies of isolated ROS [5,6] and of isolated intact retina [7,8] have shown that in response to a visible flash, photoreceptors exhibit an intrinsic near infrared scattering signal. As the ROS movement represents a morphological change in the retina, it is logical to hypothesize that the phototropic response of ROSs is a key component of the light-scattering signal [9], i.e., TRP may also originate from the ROSs.…”

Section: Introductionmentioning

confidence: 99%

Stimulus-evoked outer segment changes occur before the hyperpolarization of retinal photoreceptors

Wang

Pepperberg

et al. 2016

Biomed. Opt. Express

Self Cite

View full text Add to dashboard Cite

Transient retinal phototropism (TRP) has been predominantly observed in rod photoreceptors activated by oblique visible light stimulation. Dynamic confocal microscopy and optical coherence tomography (OCT) have revealed rod outer segment (ROS) movement as the physical source of TRP. However, the physiological source of ROS movement is still not well understood. In this study, concurrent near-infrared imaging of TRP and electroretinogram (ERG) measurement of retinal electrophysiology revealed that ROS movement occurs before the onset of the ERG a-wave, which is known to reflect the hyperpolarization of retinal photoreceptors. Moreover, substitution of normal superfusing medium with low-sodium medium reversibly blocked the photoreceptor ERG a-wave, but largely preserved the stimulus-evoked ROS movements. Our experimental results and theoretical analysis indicate that early, disc-based stages of the phototransduction cascade, which occur before the hyperpolarization of retinal photoreceptors, contribute to the TRP associated ROS movement. 259-267 (1975). 29. E. Hessel, A. Herrmann, P. Müller, P. P. Schnetkamp, and K. P. Hofmann, "The transbilayer distribution of phospholipids in disc membranes is a dynamic equilibrium evidence for rapid flip and flop movement," Eur. J.

show abstract

“…1, structure 2) was removed by bleaching. Bleaching reduces the sensitivity of a cell by depleting the supply of native pigment and by reducing the amplitude of the quantal response from the residual pigment (14)(15)(16)(17). In the absence of li-cis-retinal, this desensitization persists indefinitely (15,18) and is unresponsive to the addition of all-trans-retinal (15,19) or its removal from opsin by hydroxylamine (20,21).…”

mentioning

confidence: 99%

Relief of opsin desensitization and prolonged excitation of rod photoreceptors by 9-desmethylretinal.

Corson

Cornwall

MacNichol

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The 9-methyl group of 11-s-retinal plays a crucial role in photoexcitation of the visual pigment rhodopsin. A hydrogen-substituted analogue, 11-cis-9-desmethylretlnal, combines with opsin to form a pigment that produces abnormal photoproducts and diinished activation of the GTP-binding protein transducin in vitro. We have measured the formation of this analogue pigment in bleached salamander rods and determined the size and shape of its quantal response. In addition, we have characterized the influence of opsin and newly formed analogue pigment on the quantal response to native porphyropsin. We find that, as 11-cis-9-desmethylretinal combines with opsin in bleached rods, the amplitude of the quantal response from residual native pigment is elevated by 74.5-fold to 0.15 ± 0.09 pA, a value close to the amplitude of the quantal response before bleach (0.31 ± 0.10 pA). When activated by light, the new analogue pigment produces a quantal response that is ==30-fold smaller and decays ""5 times more slowly than that ofnative pigment in unbleached cells. We conclude that the 9-methyl group of retinal is not critical for conversion of opsin to its nondesensitizing state but that it is critical for the normal processes of activation and deactivation of metarhodopsin that give rise to the quantal response.Photoisomerization of li-cis-retinal (Fig. 1, structure 1) initiates an intramolecular rearrangement of rhodopsin that results in a catalytically active state of rhodopsin, R * (1-5). Deactivation of R* requires phosphorylation by rhodopsin kinase (6, 7) and the subsequent binding of arrestin (3,(7)(8)(9). In isolated photoreceptors, pigment activation and deactivation produce a discrete electrical response with a characteristic amplitude and time course (10,11). In an examination of the steric interactions between the apoprotein opsin and its chromophore, Ganter et al. (12) reported that 11-cis-9-desmethylretinal ( Fig. 1, structure 3) produced abnormal photoproducts and transducin activation that was 8% of the rhodopsin control. Here we examine the influence of the 9-methyl group of retinal on the amplitude and shape of the quantal response in isolated rods.To provide access to the ligand binding pocket ofopsin, the native chromophore (13) 11-cis-3,4-dehydroretinal (Fig. 1, structure 2) was removed by bleaching. Bleaching reduces the sensitivity of a cell by depleting the supply of native pigment and by reducing the amplitude of the quantal response from the residual pigment (14)(15)(16)(17). In the absence of li-cis-retinal, this desensitization persists indefinitely (15,18) and is unresponsive to the addition of all-trans-retinal (15,19) or its removal from opsin by hydroxylamine (20,21). We refer to the persistent component of desensitization that results from response attenuation and does not require the presence of a retinal-containing photoproduct as opsin desensitization. Taken together with the loss of sensitivity resulting from pigment depletion, the total loss of sensitivity is commonly referred to as ...

show abstract

Effect of bleached rhodopsin on signal amplification in rod visual receptors

Cited by 81 publications

References 30 publications

Binding of inositol phosphates to arrestin

Binding of inositol phosphates to arrestin

Stimulus-evoked outer segment changes occur before the hyperpolarization of retinal photoreceptors

Relief of opsin desensitization and prolonged excitation of rod photoreceptors by 9-desmethylretinal.

Contact Info

Product

Resources

About