| 1991 |
Rhodopsin kinase binds to the cytoplasmic loops of photoactivated rhodopsin (Rho*) — specifically the V-VI loop is crucial for kinase binding (analogous to transducin binding) — and this binding stimulates the kinase's catalytic activity. Phosphorylation by rhodopsin kinase occurs exclusively at C-terminal serine/threonine sites of Rho*. |
Enzymatic truncation of rhodopsin C-terminus and cytoplasmic loops followed by rhodopsin kinase activity assays with exogenous peptide substrates; mastoparan peptide mimicry experiments |
The Journal of biological chemistry |
High |
2071581
|
| 1991 |
The C-terminal region of the alpha subunit of transducin (Gt) interacts with photoactivated rhodopsin (Metarhodopsin II) and stabilizes the active conformation of the receptor; synthetic peptides from the alpha-t C-terminus mimic Gt in this interaction. The conformation of such a peptide bound to Metarhodopsin II was determined by 2D NMR, and mutant peptide analogs confirmed the structural model. |
Synthetic peptide binding assays, 2D NMR of peptide bound to Metarhodopsin II, peptide analog mutagenesis |
Cellular and molecular neurobiology |
High |
1782650
|
| 1995 |
Rhodopsin kinase phosphorylates photoactivated rhodopsin sequentially at C-terminal sites, with the first phosphate preferentially transferred to Ser-338, then Ser-343 and Thr-336. Arrestin binding to phosphorylated rhodopsin limits physiologically significant phosphorylation to no more than three sites; reduction of all-trans-retinal to all-trans-retinol also limits phosphorylation. |
Mass spectrometry sequencing of phosphopeptides, biochemical phosphorylation assays with rhodopsin kinase |
Biophysical chemistry |
High |
7662865
|
| 1996 |
Ca2+-bound recoverin forms a complex with rhodopsin kinase preferentially at the membrane surface, and this membrane-associated ternary complex (Ca2+-recoverin–rhodopsin kinase–membrane) leads to effective suppression of rhodopsin kinase activity, inhibiting light-dependent phosphorylation of rhodopsin. |
Biochemical membrane association assays, rhodopsin kinase activity measurements with varying membrane concentrations and recoverin |
FEBS letters |
Medium |
8617359
|
| 1998 |
Removal of rhodopsin's carboxy-terminal phosphorylation sites in transgenic mouse rods prolongs the flash response 20-fold and makes it highly variable; deletion of arrestin results in partial recovery with 100-fold slowed final recovery. These experiments establish that rhodopsin phosphorylation initiates deactivation and arrestin binding completes deactivation. |
Transgenic mouse models (C-terminal truncation, arrestin knockout), single-cell suction electrode electrophysiology of rod photoreceptors |
Eye (London, England) |
High |
9775212
|
| 1998 |
Electron cryo-microscopy and electron crystallography of 2D rhodopsin crystals revealed a 7.5 Å resolution 3D map showing seven transmembrane helices with distinct arrangement from bacteriorhodopsin: three helix layers near the intracellular (G protein-interacting) side, a retinal-binding cavity open toward the extracellular side, closed intracellularly by the long tilted helix 3, and closed extracellularly by the loop 4-5 linked by a disulfide bridge to the extracellular end of helix 3. |
Electron cryo-microscopy, image processing, and electron crystallography of 2D crystals |
Eye (London, England) |
High |
9775210
|
| 2001 |
Picosecond time-resolved spectroscopy of 11-cis locked rhodopsin analogs established that cis-trans isomerization of the 11-cis retinal chromophore is the primary photochemical reaction in rhodopsin. Femtosecond pump-probe spectroscopy showed formation of photorhodopsin within 200 fs and that the photoisomerization proceeds via a vibrationally coherent process. The protein environment facilitates efficient isomerization relative to retinal in solution. |
Picosecond time-resolved spectroscopy, femtosecond transient absorption (pump-probe), femtosecond fluorescence spectroscopy, locked retinal analogs |
Biochemistry. Biokhimiia |
High |
11743865
|
| 2001 |
X-ray crystal structure of bovine rhodopsin revealed the 3D arrangement of the 7-transmembrane helical bundle as a GPCR, showing the 11-cis-retinal chromophore covalently bound via Schiff base in a binding pocket, and demonstrated that rhodopsin's helix arrangement differs from bacteriorhodopsin despite both having heptahelical bundles. |
X-ray crystallography |
Current opinion in structural biology |
High |
11495733
|
| 2015 |
When reconstituted into large unilamellar vesicles, rhodopsin functions as an ATP-independent phospholipid scramblase, accelerating transbilayer translocation of common phospholipids by more than 1000-fold to rates exceeding 10,000 phospholipids per rhodopsin per second. |
Reconstitution of rhodopsin into large unilamellar vesicles, phospholipid scramblase activity assay |
Photochemical & photobiological sciences |
High |
26179029
|
| 2015 |
EPR spectroscopy with spin labeling identified light-induced transmembrane helical movements in rhodopsin upon photoactivation, characterizing functional loop dynamics, millisecond-timescale conformational changes, effects of partial agonists on opsin, and lipid interactions, establishing the structural basis of GPCR activation. |
Site-directed spin labeling, EPR spectroscopy, pulsed EPR (DEER/PELDOR) |
Photochemical & photobiological sciences |
Medium |
26140679
|
| 2018 |
Crystal structure of pharmacologically stabilized opsin at 2.4 Å resolution revealed an open channel connecting the orthosteric retinal binding site with the membrane and the intradiscal lumen, sufficient in size to permit exchange of hydrophobic ligands such as retinal. Small molecule pharmacological chaperones bind at the orthosteric binding site and stabilize the receptor. |
X-ray crystallography (2.4 Å resolution), virtual and thermofluor screening for stabilizing ligands, chemical modification of stabilizing compounds |
Proceedings of the National Academy of Sciences of the United States of America |
High |
29555765
|
| 2022 |
Visual arrestin (ARR1) binding to light-activated phosphorylated rhodopsin facilitates rhodopsin dephosphorylation in vivo. In Arr1 knockout mouse rods, rhodopsin remained phosphorylated even after 3 hours in darkness, compared to near-complete dephosphorylation within 1 hour in wild-type. This effect required ARR1 binding competence (ARR1-3A mutant with binding rescued dephosphorylation), and was independent of transducin signaling or protein phosphatase 2A downregulation. |
Arrestin knockout mice, isoelectric focusing to resolve phosphorylated rhodopsin species, transducin double-knockout controls, ARR1-3A binding-competent mutant rescue |
The Journal of neuroscience |
High |
35332081
|
| 2023 |
Ubiquitylation of lysine residues on P23H misfolded rhodopsin drives its accelerated protein turnover/degradation. Mutation of all 11 lysine residues to arginine (K-null P23H) significantly reduced ubiquitylation and slowed protein turnover compared to intact P23H rhodopsin. Wild-type rhodopsin with all lysines mutated to arginine also showed significantly reduced ubiquitylation. |
Transfection of HEK293 cells with K-null P23H rhodopsin constructs, ubiquitylation assays, cycloheximide chase analysis of protein turnover |
Advances in experimental medicine and biology |
Medium |
37440077
|
| 2025 |
The K296E rhodopsin mutant (constitutively active) mislocalizes and forms protein aggregates in photoreceptor cells in knockin mice, contributing to retinal degeneration. Aggregation propensity of K296E rhodopsin was confirmed in vitro and was dependent on species background: mouse and human rhodopsin backgrounds showed aggregation, while bovine background did not, indicating species-specific differences in aggregation. |
Knockin mouse generation, PROTEOSTAT dye staining for protein aggregates, in vitro aggregation assays across species backgrounds |
FASEB journal |
Medium |
40667763
|