Insights into congenital stationary night blindness based on the structure of G90D rhodopsin

Singhal, Ankita; Ostermaier, Martin K.; Vishnivetskiy, Sergey A.; Panneels, Valérie; Homan, Kristoff T.; Tesmer, John J.G.; Veprintsev, Dmitry B.; Deupí, Xavier; Gurevich, Vsevolod V.; Schertler, Gebhard F. X.; Standfuss, Joerg

doi:10.1038/embor.2013.44

Cited by 79 publications

(92 citation statements)

References 36 publications

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“…Interestingly, upon addition of 11-cis retinal, the transition melting temperature of T94I 2.61 rhodopsin increased only from 49 to 53°C, whereas the effect on WT rhodopsin was much more pronounced, with a shift of the transition temperature from 53 to 63°C. We have observed a similar destabilizing effect of the G90D 2.57 mutation on the rhodopsin dark state [16]. However, in contrast to G90D 2.57 , the T94I 2.61 mutation does not increase the stability of the opsin state, presumably because the introduced isoleucine is unable to form a stabilizing salt bridge interaction with K296 7.43 .…”

Section: Effect Of Csnb Mutants On Stability Of the Rhodopsin Dark Statementioning

confidence: 54%

“…As in our previous rhodopsin crystallization projects, all constructs used in this study also contain an additional thermostabilizing disulfide bridge, depicted as (c-c), to enhance the stability [18] and crystallizability [19] without changing the rhodopsin activation pathway [20]. Overall T94I 2.61 rhodopsin adopts the conformation of metarhodopsin-II obtained by soaking opsin crystals with all-trans retinal (rmsd of a atoms = 0.353) [17] and compares well to constitutively active M257Y metarhodopsin-II (rmsd of a atoms = 0.35) [21] and the overall fold of the CSNB mutant G90D 2.57 (rmsd of a atoms = 0.29) [16]. However, the effect of the T94I 2.61 mutation on the retinal binding pocket is strikingly different to that of G90D 2.57 (Fig 1).…”

Section: Resultsmentioning

confidence: 99%

“…In a previous work, we presented the crystal structure of the CSNB-causing G90D 2.57 (superscript denotes Ballesteros Weinstein numbering) rhodopsin mutant [16]. This structure visualized how the mutated aspartate in TM2 forms a salt bridge with residue K296 7.43 …”

Section: à11mentioning

confidence: 99%

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Structural role of the T94I rhodopsin mutation in congenital stationary night blindness

et al. 2016

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Congenital stationary night blindness (CSNB) is an inherited and non-progressive retinal dysfunction. Here, we present the crystal structure of CSNB-causing T94I2.61 rhodopsin in the active conformation at 2.3 Å resolution. The introduced hydrophobic side chain prolongs the lifetime of the G protein activating metarhodopsin-II state by establishing a direct van der Waals contact with K296, the site of retinal attachment. This is in stark contrast to the light-activated state of the CSNB-causing G90D2.57 mutation, where the charged mutation forms a salt bridge with K296 7.43. To find the common denominator between these two functional modifications, we combined our structural data with a kinetic biochemical analysis and molecular dynamics simulations. Our results indicate that both the charged G90D2.57 and the hydrophobic T94I 2.61 mutation alter the dark state by weakening the interaction between the Schiff base (SB) and its counterion E113 3.28 . We propose that this interference with the tight regulation of the dim light photoreceptor rhodopsin increases background noise in the visual system and causes the loss of night vision characteristic for CSNB patients.

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Section: Effect Of Csnb Mutants On Stability Of the Rhodopsin Dark Statementioning

confidence: 54%

Section: Resultsmentioning

confidence: 99%

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Structural role of the T94I rhodopsin mutation in congenital stationary night blindness

et al. 2016

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“…4, Right Middle Inset), whose relative position has been implicated in arrestin-biased agonism in β-adrenergic receptors (36) and arrestin binding to rhodopsin (37). Also, the introduction of a salt-bridge between TM3 and TM7 by the night blindness causing rhodopsin mutant G90D reduces its ability to bind arrestin (38,39). Together, the finger and lariat loop could thus create an activity sensor that specifically interacts with helices critical for GPCR activation.…”

Section: Resultsmentioning

confidence: 99%

Functional map of arrestin-1 at single amino acid resolution

Ostermaier

Peterhans

Jaussi

et al. 2014

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

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Arrestins function as adapter proteins that mediate G proteincoupled receptor (GPCR) desensitization, internalization, and additional rounds of signaling. Here we have compared binding of the GPCR rhodopsin to 403 mutants of arrestin-1 covering its complete sequence. This comprehensive and unbiased mutagenesis approach provides a functional dimension to the crystal structures of inactive, preactivated p44 and phosphopeptide-bound arrestins and will guide our understanding of arrestin-GPCR complexes. The presented functional map quantitatively connects critical interactions in the polar core and along the C tail of arrestin. A series of amino acids (Phe375, Phe377, Phe380, and Arg382) anchor the C tail in a position that blocks binding of the receptor. Interaction of phosphates in the rhodopsin C terminus with Arg29 controls a C-tail exchange mechanism in which the C tail of arrestin is released and exposes several charged amino acids (Lys14, Lys15, Arg18, Lys20, Lys110, and Lys300) for binding of the phosphorylated receptor C terminus. In addition to this arrestin phosphosensor, our data reveal several patches of amino acids in the finger (Gln69 and Asp73-Met75) and the lariat loops (L249-S252 and Y254) that can act as direct binding interfaces. A stretch of amino acids at the edge of the C domain (Trp194-Ser199, Gly337-Gly340, Thr343, and Thr345) could act as membrane anchor, binding interface for a second rhodopsin, or rearrange closer to the central loops upon complex formation. We discuss these interfaces in the context of experimentally guided docking between the crystal structures of arrestin and light-activated rhodopsin.visual system | scanning mutagenesis | membrane receptor | cell signaling | protein engineering T he human genome encodes more than 800 G protein-coupled receptors (GPCRs), which mediate signaling between cells and provide an important link to our environment as the principal receptors for taste, smell, and vision. The visual system with its photoreceptor rhodopsin is an excellent system to understand GPCR signaling, as detailed information exists on the structures and dynamic interactions of the protein constituents (1). G protein-mediated signaling by light-activated rhodopsin is terminated by a process that begins with the phosphorylation of rhodopsin's C terminus by the rhodopsin kinase GRK1. The phosphorylated, light-activated rhodopsin binds then to arrestin-1, which stops signaling by occluding the G protein-binding site. Further cloning efforts yielded two ubiquitously expressed nonvisual arrestins (arrestin-2 and arrestin-3 or β-arrestin-1 and β-arrestin-2) and the cone-specific arrestin-4. It seems clear today that most GPCRs share a common mechanism of signal termination involving receptor phosphorylation and the binding of arrestins. Arrestin-bound receptors may be internalized and degraded, internalized and recycled, and/or initiate G proteinindependent signaling (2).In recent years there has been tremendous progress in the structure determination of active GPCR states includ...

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“…With the exception of squid rhodopsin, TMI networks were found only in structures of activated rhodopsins (Fig. S2) (4,6,40). In opsin and rhodopsin these networks trace a path that originates from extracellular residues above the retinal-binding pocket, passes through the buried Lys296 that couples to the retinal ligand, extends through structurally conserved waters in the receptor core, and terminates at the intracellular D/ERY motif ( Fig.…”

Section: Significancementioning

confidence: 99%

Buried ionizable networks are an ancient hallmark of G protein-coupled receptor activation

Isom¹,

Dohlman

2015

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

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Seven-transmembrane receptors (7TMRs) have evolved in prokaryotes and eukaryotes over hundreds of millions of years. Comparative structural analysis suggests that these receptors may share a remote evolutionary origin, despite their lack of sequence similarity. Here we used structure-based computations to compare 221 7TMRs from all domains of life. Unexpectedly, we discovered that these receptors contain spatially conserved networks of buried ionizable groups. In microbial 7TMRs these networks are used to pump ions across the cell membrane in response to light. In animal 7TMRs, which include light-and ligand-activated G protein-coupled receptors (GPCRs), homologous networks were found to be characteristic of activated receptor conformations. These networks are likely relevant to receptor function because they connect the ligandbinding pocket of the receptor to the nucleotide-binding pocket of the G protein. We propose that agonist and G protein binding facilitate the formation of these electrostatic networks and promote important structural rearrangements such as the displacement of transmembrane helix-6. We anticipate that robust classification of activated GPCR structures will aid the identification of ligands that target activated GPCR structural states.7-transmembrane receptor | G protein-coupled receptor | buried charge | structural bioinformatics | molecular evolution S even-transmembrane receptors (7TMRs) are present in all domains of life. In archaea and bacteria these receptors convert light energy into transmembrane ion gradients or intracellular signaling cascades. In humans 7TMRs comprise a family of more than 800 G protein-coupled receptors (GPCRs) that detect extracellular signals such as odorants, taste, light, hormones, and neurotransmitters. Although microbial and eukaryotic 7TMRs lack sequence similarity, their 3D folds share a degree of similarity that often is observed in remote evolutionary relationships identified by structure comparison algorithms (1).Recent breakthroughs in membrane protein crystallography have advanced our understanding of GPCR function by providing models of unactivated and activated receptor conformations (2-8). However, structure-based approaches for systematically quantifying differences between GPCR activation states are lacking. Here we introduce a computational approach that correlates GPCR activation with networks of electrostatic interactions in the receptor core. We show that membrane-spanning networks of ionizable residues, which we find are a common feature of microbial 7TMRs, also represent a unique signature of GPCR activation that is likely to be essential to receptor function.The molecular changes that accompany 7TMR activation were studied initially in bacteriorhodopsin and rhodopsin, the first microbial 7TMR and GPCR to be crystallized (9-11). More recently, a rapid expansion of GPCR structural information has revealed several molecular switches and structural features that are thought to be indicative of receptor activation. These include the ionic loc...

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Insights into congenital stationary night blindness based on the structure of G90D rhodopsin

Cited by 79 publications

References 36 publications

Structural role of the T94I rhodopsin mutation in congenital stationary night blindness

Structural role of the T94I rhodopsin mutation in congenital stationary night blindness

Functional map of arrestin-1 at single amino acid resolution

Buried ionizable networks are an ancient hallmark of G protein-coupled receptor activation

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