Rhodopsin dimers in native disc membranes

Fotiadis, Dimitrios; Liang, Yan; Filipek, Sławomir; Saperstein, David A.; Engel, Andréas; Palczewski, Krzysztof

doi:10.1038/421127a

Cited by 707 publications

(687 citation statements)

References 5 publications

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“…Also, the possible asymmetry introduced by binding of a single G protein per activated homomer has not been considered. 32,42,43 . For GpHrs, both TMD-alone and ECD-alone constructs have been shown to dimerize efficiently 7,26 .…”

Section: Discussionmentioning

confidence: 99%

Evidence for activity-regulated hormone-binding cooperativity across glycoprotein hormone receptor homomers

et al. 2012

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Glycoprotein hormone receptors show strong negative cooperativity. As a consequence, at physiological hormone concentrations, a single agonist binds to a receptor dimer. Here we present evidence that constitutively active receptors lose cooperative allosteric regulation in direct relation with their basal activity. The most constitutive mutants lost nearly all cooperativity and showed an increase of initial tracer binding, reflecting the ability of each protomer to bind with equal affinity. Allosteric interaction between the protomers takes place at the transmembrane domain. The allosteric message resulting from hormone binding to the ectodomain of one protomer travels 'downward' to its transmembrane domain, before affecting the transmembrane domain of the other protomer. This results in transmission of an 'upward' message lowering the binding affinity of the ectodomain of the second protomer. our results demonstrate a direct relation between the conformational changes associated with activation of the transmembrane domain and the allosteric behaviour of glycoprotein hormone receptors dimers.

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Section: Discussionmentioning

confidence: 99%

Evidence for activity-regulated hormone-binding cooperativity across glycoprotein hormone receptor homomers

et al. 2012

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“…At 37ºC, G90V bicelles and N55K bicelles showed enhanced thermal stability when compared to the DM-solubilized samples. Thermal decay process involves protein conformational changes, retinal isomerization and eventually hydrolysis of SB and chromophore release 20,38,39 . We find that t 1/2 of G90V bicelles and N55K bicelles suffers a 3 and 4 fold increase respectively when compared to the detergentsolubilized samples (Figure 6a and Table 2).…”

Section: Thermal Stability Of Wt and G90v N55k In Dm And In Dmpc/dhpmentioning

confidence: 99%

Phospholipid Bicelles Improve the Conformational Stability of Rhodopsin Mutants Associated with Retinitis Pigmentosa

et al. 2015

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Mutations in the visual photoreceptor rhodopsin are the cause of the retinal degenerative disease retinitis pigmentosa. Some naturally occurring mutations can lead to protein conformational instability. Two such mutations, N55K and G90V, in the first and second transmembrane helices of the receptor, have been associated with sector and classical retinitis pigmentosa, respectively, and showed enhanced thermal sensitivity. We have carefully analyzed the effect of phospholipid bicelles on the stability and ligand binding properties of these two mutants and compared it with those of the detergent-solubilized samples. We have used a phospholipid bilayer consisting of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) and 1,2dihexanoyl-sn-glycero-3-phosphocholine (DHPC). We find that DMPC/DHPC bicelles dramatically increase the thermal stability of the rhodopsin mutants G90V and N55K. The chromophore stability and regeneration of the mutants were also increased in bicelles when compared to their behavior in a dodecyl maltoside detergent solution. The retinal release process was slowed in bicelles, and chromophore entry, after illumination, was improved for the G90V mutant but not for N55K. Furthermore, fluorescence spectroscopy measurements showed that bicelles allowed more exogenous retinal binding to the photoactivated G90V mutant than in a detergent solution. In contrast, N55K could not reposition any chromophore either in the detergent or in bicelles. The results demonstrate that DMPC/DHPC bicelles can counteract the destabilizing effect of the disease-causing mutations and can modulate the structural changes in the ensuing receptor photoactivation in a distinct specific manner for different retinitis pigmentosa mutant phenotypes.

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“…Single protein can be observed in the membrane with this methodology since the resolution is 0.1nm vertically and 0.5nm horizontally. For example, AFM has provided an understanding of oligomeric Rho protein structure in native membranes [78]. Recent progress in time-lapse AFM showed, in real time, the change in height of the pore protrusion from the membrane of cytolysin within its formation [79].…”

Section: Future Challengesmentioning

confidence: 99%

What do diffusion measurements tell us about membrane compartmentalisation? Emergence of the role of interprotein interactions

2008

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The techniques of diffusion analysis based on optical microscopy approaches have revealed a great diversity of the dynamic organisation of cell membranes. For a long period, two frameworks have dominated the way of representing the membrane structure: the membrane skeleton fences and the lipid raft models. Progresses in the methods of data analysis have shed light on the features and consequently the possible origin of membrane domains: Inter-protein interactions play a role in confinement. Innovative developments pushing forward the spatiotemporal resolution limits are currently emerging, which are likely to provide in the future a detailed understanding of the intimate functional dynamic organisation of the cell membrane. Keywords Membrane domain . Diffusion . Protein interaction OverviewThe main function of membranes is to generate close compartments: The cell itself (by the plasma membrane) and also the nucleus (by nuclear envelope), the Golgi apparatus, the endoplasmic reticulum, various organelles or the vesicles which are involved in transport processes. Membranes delimit these structures and allow them to have a different composition from the rest of the cell by restricting the diffusion of ions and macromolecules. The specific transport of molecules or information across the membrane is devoted to membrane proteins. Membranes are essentially composed of lipid and proteins, each of them representing about 50% in weight. Lipids are amphiphilic molecules that spontaneously form a bilayer in water. Among the variety of lipids, cholesterol has a specific place since it is particularly abundant in eukaryotic cells. Cholesterol can modify the lipid molecular order [1] and is presumed to participate in lipid micro-phase separation (rafts) [2][3][4][5].Since the structure of biological membranes is maintained by non-covalent bonds, they have first been considered as a fluid lipid bilayer in which embedded proteins are free to diffuse [6]. After the advent of this fluid mosaic model postulating a random distribution of membrane molecules [6], experimental evidence showed that the proteins and lipids are distributed heterogeneously in the membrane. For example, incomplete recoveries were systematically observed in fluorescence recovery after photobleaching (FRAP; see "Appendix 1") experiments. The first indication of the presence of micrometer-sized domains was obtained by FRAP. Yechiel and Edidin found a decrease of the mobile fraction with increasing radius of the bleaching spot ([7, 8] and see "Appendix 1").The huge diversity of lipids and proteins implies that a very large number of combinatorial interactions can occur between them [9]. Since all lipids and proteins do not J Chem Biol (2008) [14,15]. Interactions of membrane proteins with the cytoskeleton or with the glycocalyx can also affect the membrane organisation and are likely to play a confining role [16]. A significant challenge of cell biology is to characterise and to understand not only the origin but also the role of these micrometric ...

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Rhodopsin dimers in native disc membranes

Cited by 707 publications

References 5 publications

Evidence for activity-regulated hormone-binding cooperativity across glycoprotein hormone receptor homomers

Evidence for activity-regulated hormone-binding cooperativity across glycoprotein hormone receptor homomers

Phospholipid Bicelles Improve the Conformational Stability of Rhodopsin Mutants Associated with Retinitis Pigmentosa

What do diffusion measurements tell us about membrane compartmentalisation? Emergence of the role of interprotein interactions

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