0000000000141634

AUTHOR

Angelika Schmitt

showing 4 related works from this author

Calcium-Dependent Assembly of Centrin-G-Protein Complex in Photoreceptor Cells

2002

Photoexcitation of rhodopsin activates a heterotrimeric G-protein cascade leading to cyclic GMP hydrolysis in vertebrate photoreceptors. Light-induced exchanges of the visual G-protein transducin between the outer and inner segment of rod photoreceptors occur through the narrow connecting cilium. Here we demonstrate that transducin colocalizes with the Ca(2+)-binding protein centrin 1 in a specific domain of this cilium. Coimmunoprecipitation, centrifugation, centrin overlay, size exclusion chromatography, and kinetic light-scattering experiments indicate that Ca(2+)-activated centrin 1 binds with high affinity and specificity to transducin. The assembly of centrin-G-protein complex is medi…

Lightgenetic structuresChromosomal Proteins Non-HistoneMacromolecular SubstancesImmunoprecipitationG proteinCentrifugationPlasma protein bindingBiologyRetinaSubstrate SpecificityRats Sprague-DawleyMiceHeterotrimeric G proteinCalcium-binding proteinAnimalsScattering RadiationTransducinMicroscopy ImmunoelectronCell Growth and DevelopmentMolecular BiologyCalcium-Binding ProteinsCell BiologyHeterotrimeric GTP-Binding ProteinsPrecipitin TestsRatsCell biologyMice Inbred C57BLMolecular WeightRhodopsinCentrinChromatography Gelbiology.proteinCalciumCattlesense organsTransducinPhotoreceptor Cells VertebrateProtein BindingSignal TransductionMolecular and Cellular Biology
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Identification of Novel Molecular Components of the Photoreceptor Connecting Cilium by Immunoscreens

2002

Abstract The connecting cilium of photoreceptor cells is the only intracellular link between the morphologically, functionally and biochemically different compartments of the inner and outer segments. The non-motile modified cilium plays an important role in the organization and the function of photoreceptor cells, namely in delivery and turnover of enzymes and substrates of the visual transduction cascade, and the photosensitive membranes of the outer segment. The protein components of the cilium participate in the intracellular transport through the cilium, in the outer segment disk morphogenesis and in the maintenance of discrete membrane domains. In order to identify yet unknown cytoske…

Photoreceptor Connecting CiliumAdenomatous Polyposis Coli ProteinXenopus ProteinsBiologyPhotoreceptor cellRats Sprague-DawleyMiceCellular and Molecular NeurosciencemedicineAnimalsDrosophila ProteinsCiliaCloning MolecularCytoskeletonMicrotubule-Associated Protein 4CytoskeletonGene LibraryRetinaCiliumCalcium-Binding ProteinsDynactin ComplexSensory SystemsRatsCell biologyMice Inbred C57BLOphthalmologymedicine.anatomical_structureCentrinsense organsMicrotubule-Associated ProteinsPhotoreceptor Cells VertebrateVisual phototransductionExperimental Eye Research
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Rhodopsin transport in the membrane of the connecting cilium of mammalian photoreceptor cells

2000

The transport of the photopigment rhodopsin from the inner segment to the photosensitive outer segment of vertebrate photoreceptor cells has been one of the main remaining mysteries in photoreceptor cell biology. Because of the lack of any direct evidence for the pathway through the photoreceptor cilium, alternative extracellular pathways have been proposed. Our primary aim in the present study was to resolve rhodopsin trafficking from the inner to the outer segment. We demonstrate, predominantly by high-sensitive immunoelectron microscopy, that rhodopsin is also densely packed in the membrane of the photoreceptor connecting cilium. Present prominent labeling of rhodopsin in the ciliary mem…

RhodopsinOpsingenetic structuresPhotoreceptor Connecting CiliumImmunoblottingMolecular Sequence Datamacromolecular substancesMyosinsBiologyPhotoreceptor cellRats Sprague-DawleyMiceRetinal Rod Photoreceptor CellsStructural BiologymedicineAnimalsHumansPhotopigmentAmino Acid SequenceCiliaMicroscopy ImmunoelectronCiliary membraneCiliumRod OpsinsAntibodies MonoclonalDyneinsBiological TransportCell BiologyMiddle AgedRod Cell Outer SegmentActin cytoskeletonImmunohistochemistryActinseye diseasesRatsCell biologyMice Inbred C57BLmedicine.anatomical_structureRhodopsinMyosin VIIabiology.proteinCattleFemalesense organsRetinitis PigmentosaCell Motility and the Cytoskeleton
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Evidence for Myosin VIIa-Driven Transport of Rhodopsin in the Plasma Membrane of the Photoreceptor-Connecting Cilium

2007

Defects in the gene encoding for the unconventional myosin VIIa leads to human Usher syndrome 1B, the most common form of hereditary combined blindness and deafness. To determine cellular function of myosin VIIa, we have investigated the subcellular localization of myosin VIIa in spacial relation relationship to potentially interacting proteins in mammalian photoreceptor cells. Western blot analysis of the axonemal fraction of photoreceptor cells by Western blot show that myosin VIIa and actin, as well as opsin, were present in the ciliary portion of the photoreceptors. Improved immunoelectron microscopy revealed that in mammalian photoreceptor cells, myosin VIIa was localized at the membra…

Myosin light-chain kinasegenetic structuresbiologyPhotoreceptor Connecting CiliumImmunoelectron microscopymacromolecular substancesPhotoreceptor outer segmenteye diseasesCell biologyRhodopsinMyosinotorhinolaryngologic diseasesbiology.proteinsense organsCiliary membraneActin
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