Arrestin can act as a regulator of rhodopsin photochemistry

Sommer, Monika; Farrens, David

doi:10.1016/j.visres.2006.08.031

Cited by 40 publications

(44 citation statements)

References 80 publications

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“…These results confirm previous speculations about the role of these protein regions based on studies using full-length G protein and arrestin (31,75). Importantly, our observations indicate that the well known phenomenon of MII "trapping" by G protein and arrestin needs to be reevaluated (3,33,34,52,56,59,76). Our results indicate that G protein and arrestin trapping cannot simply be ascribed to these proteins preventing ATR release from the activated MII receptor.…”

Section: Occupancy Of the Cytoplasmic Binding Cleft Of Opsin By Eithesupporting

confidence: 90%

Conformational Selection and Equilibrium Governs the Ability of Retinals to Bind Opsin

Schafer¹,

Farrens

2015

Journal of Biological Chemistry

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Background: A current hypothesis proposes that retinal binding to opsin requires transient activation of receptor. Results: Our data show that an active conformation only promotes agonist binding; inverse agonist binding is impaired with increased relative fraction of active receptor. Conclusion: Retinal isomers must match opsin conformation to form a stable complex. Significance: Rhodopsin displays conformational selection for retinal binding similar to other ligand-binding GPCRs.

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Section: Occupancy Of the Cytoplasmic Binding Cleft Of Opsin By Eithesupporting

confidence: 90%

Conformational Selection and Equilibrium Governs the Ability of Retinals to Bind Opsin

Schafer¹,

Farrens

2015

Journal of Biological Chemistry

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“…This band is a marker of the Meta III intermediate, a decay product of Meta II (47). In the presence of arrestin, no such band occurred, supporting the notion that Meta III formation is prevented in the presence of arrestin (48).…”

Section: B) Analogously To the 1644 CMsupporting

confidence: 60%

Formation and Decay of the Arrestin·Rhodopsin Complex in Native Disc Membranes

Beyrière

Sommer

Szczepek

et al. 2015

Journal of Biological Chemistry

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Background:Arrestins regulate the signaling of rhodopsin-like G protein-coupled receptors. Results: We isolated the infrared spectra of rhodopsin⅐arrestin-1 complex formation. Conclusion: Complex formation stabilizes the active receptor and is accompanied by ␤-sheet loss. During decay, arrestin stabilizes only half of the receptor population in the active form. Significance: Our new approach extends knowledge from x-ray structures and other recent spectroscopic studies.

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“…Furthermore, serine and threonine residues at the C-terminus (349-353) are shared in common with amphibians and reptiles but were lost in placentals and marsupials (Table S3). These additional residues could be targets for phosphorylation, which in turn could affect the binding affinity of arrestin, a regulator of rhodopsin photochemistry (Sommer & Farrens, 2006). In contrast, the echidna sequence only shares four residues with therian mammals at more variable sites, where amino acids differ between Theria and nonmammals: 99, 100, 228, and 308 (Table S3).…”

Section: Echidna Rhodopsin Sequence Analysismentioning

confidence: 99%

Functional characterization of the rod visual pigment of the echidna (Tachyglossus aculeatus), a basal mammal

et al. 2012

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Monotremes are the most basal egg-laying mammals comprised of two extant genera, which are largely nocturnal. Visual pigments, the first step in the sensory transduction cascade in photoreceptors of the eye, have been examined in a variety of vertebrates, but little work has been done to study the rhodopsin of monotremes. We isolated the rhodopsin gene of the nocturnal short-beaked echidna (Tachyglossus aculeatus) and expressed and functionally characterized the protein in vitro. Three mutants were also expressed and characterized: N83D, an important site for spectral tuning and metarhodopsin kinetics, and two sites with amino acids unique to the echidna (T158A and F169A). The k max of echidna rhodopsin (497.9 6 1.1 nm) did not vary significantly in either T158A (498.0 6 1.3 nm) or F169A (499.4 6 0.1 nm) but was redshifted in N83D (503.8 6 1.5 nm). Unlike other mammalian rhodopsins, echidna rhodopsin did react when exposed to hydroxylamine, although not as fast as cone opsins. The retinal release rate of light-activated echidna rhodopsin, as measured by fluorescence spectroscopy, had a half-life of 9.5 6 2.6 min À1 , which is significantly shorter than that of bovine rhodopsin. The half-life of the N83D mutant was 5.1 6 0.1 min À1 , even shorter than wild type. Our results show that with respect to hydroxylamine sensitivity and retinal release, the wild-type echidna rhodopsin displays major differences to all previously characterized mammalian rhodopsins and appears more similar to other nonmammalian vertebrate rhodopsins such as chicken and anole. However, our N83D mutagenesis results suggest that this site may mediate adaptation in the echidna to dim light environments, possibly via increased stability of light-activated intermediates. This study is the first characterization of a rhodopsin from a most basal mammal and indicates that there might be more functional variation in mammalian rhodopsins than previously assumed.

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Arrestin can act as a regulator of rhodopsin photochemistry

Cited by 40 publications

References 80 publications

Conformational Selection and Equilibrium Governs the Ability of Retinals to Bind Opsin

Conformational Selection and Equilibrium Governs the Ability of Retinals to Bind Opsin

Formation and Decay of the Arrestin·Rhodopsin Complex in Native Disc Membranes

Functional characterization of the rod visual pigment of the echidna (Tachyglossus aculeatus), a basal mammal

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