0000000000123181

AUTHOR

Philipp Trojan

showing 5 related works from this author

Differential expression and interaction with the visual G-protein transducin of centrin isoforms in mammalian photoreceptor cells.

2004

Photoisomerization of rhodopsin activates a heterotrimeric G-protein cascade leading to closure of cGMP-gated channels and hyperpolarization of photoreceptor cells. Massive translocation of the visual G-protein transducin, Gt, between subcellular compartments contributes to long term adaptation of photoreceptor cells. Ca(2+)-triggered assembly of a centrin-transducin complex in the connecting cilium of photoreceptor cells may regulate these transducin translocations. Here we demonstrate expression of all four known, closely related centrin isoforms in the mammalian retina. Interaction assays revealed binding potential of the four centrin isoforms to Gtbetagamma heterodimers. High affinity b…

Rhodopsingenetic structuresLightBlotting WesternBiologyBiochemistryRetinaRats Sprague-DawleyMiceCalcium-binding proteinHeterotrimeric G proteinmedicineAnimalsProtein IsoformsScattering RadiationCiliaTransducinMicroscopy ImmunoelectronMolecular BiologyCyclic GMPGlutathione TransferaseCentrosomeRetinaChromatographyDose-Response Relationship DrugReverse Transcriptase Polymerase Chain ReactionCiliumCalcium-Binding ProteinsCell BiologySequence Analysis DNARod Cell Outer SegmentRecombinant ProteinsCell biologyRatsMice Inbred C57BLKineticsProtein Transportmedicine.anatomical_structureMicroscopy FluorescenceRhodopsinCentrosomeCentrinbiology.proteinCalciumCattleElectrophoresis Polyacrylamide Gelsense organsTransducinProtein BindingThe Journal of biological chemistry
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Light-dependent CK2-mediated phosphorylation of centrins regulates complex formation with visual G-protein.

2008

AbstractCentrins are Ca2+-binding EF-hand proteins. All four known centrin isoforms are expressed in the ciliary apparatus of photoreceptor cells. Cen1p and Cen2p bind to the visual G-protein transducin in a strictly Ca2+-dependent way, which is thought to regulate light driven movements of transducin between photoreceptor cell compartments. These relatively slow motile processes represent a novel paradigm in light adaptation of photoreceptor cells.Here we validated specific phosphorylation as a novel regulator of centrins in photoreceptors. Centrins were differentially phosphorylated during photoreceptor dark adaptation. Inhibitor treatments revealed protein kinase CK2 as the major protein…

genetic structuresLightG proteinVisionChromosomal Proteins Non-HistoneBlotting WesternDark AdaptationBiologySignal transductionMicrotubulesPhotoreceptor cellMass SpectrometryCa2+-binding proteinsSubstrate SpecificityRats Sprague-DawleyMiceHeterotrimeric G proteinmedicineAnimalsCiliaTransducinPhosphorylationProtein kinase ACasein Kinase IIFluorescent Antibody Technique IndirectMicroscopy ImmunoelectronMolecular BiologyCytoskeletonCiliumCalcium-Binding ProteinsCell BiologyCell biologyRatsMice Inbred C57BLmedicine.anatomical_structureCentrinPhosphorylationHeterotrimeric G-proteinCalciumCattleTransducinsense organsMolecular translocationPhotoreceptor Cells VertebrateProtein BindingBiochimica et biophysica acta
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Centrins in retinal photoreceptor cells: regulators in the connecting cilium.

2008

Changes in the intracellular Ca2+ concentration regulate the visual signal transduction cascade directly or more often indirectly through Ca2+-binding proteins. Here we focus on centrins, which are members of a highly conserved subgroup of the EF-hand superfamily of Ca2+-binding proteins in photoreceptor cells of the vertebrate retina. Centrins are commonly associated with centrosome-related structures. In mammalian retinal photoreceptor cells, four centrin isoforms are expressed as prominent components in the connecting cilium linking the light-sensitive outer segment compartment with the metabolically active inner segment compartment. Our data indicate that Ca2+-activated centrin isoforms…

Gene isoformgenetic structuresChromosomal Proteins Non-HistoneBiologyContractile ProteinsHeterotrimeric G proteinmedicineCompartment (development)AnimalsHumansCiliaEye ProteinsVision OcularRetinaCalcium-Binding ProteinsSensory SystemsCell biologyOphthalmologymedicine.anatomical_structureCentrinCalciumsense organsTransducinSignal transductionIntracellularPhotoreceptor Cells VertebrateProgress in retinal and eye research
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Centrins, gatekeepers for the light-dependent translocation of transducin through the photoreceptor cell connecting cilium

2006

Centrins are members of a highly conserved subgroup of the EF-hand superfamily of Ca(2+)-binding proteins commonly associated with centrosome-related structures. In the retina, centrins are also prominent components of the photoreceptor cell ciliary apparatus. Centrin isoforms are differentially localized at the basal body and in the lumen of the connecting cilium. All molecular exchanges between the inner and outer segments occur through this narrow connecting cilium. Ca(2+)-activated centrin isoforms bind to the visual heterotrimeric G-protein transducin via an interaction with the betagamma-subunit. Ca(2+)-dependent assemblies of centrin/G-protein complexes may regulate the transducin mo…

Gene isoformPhotoreceptorsgenetic structuresPhotoreceptor cellHeterotrimeric G proteinConnecting ciliummedicineCentrinBasal bodyAnimalsPhotoreceptor CellsCiliaTransducinPhosphorylationVision OcularCentrosomeRetinaChemistryLight-dependent translocationCiliumCalcium-Binding ProteinsSensory SystemsCell biologyProtein TransportOphthalmologymedicine.anatomical_structureCentrinVertebratesTransducinsense organsPhotic StimulationVision Research
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RPGR ORF15 isoform co-localizes with RPGRIP1 at centrioles and basal bodies and interacts with nucleophosmin

2005

The ORF15 isoform of RPGR (RPGR(ORF15)) and RPGR interacting protein 1 (RPGRIP1) are mutated in a variety of retinal dystrophies but their functions are poorly understood. Here, we show that in cultured mammalian cells both RPGR(ORF15) and RPGRIP1 localize to centrioles. These localizations are resistant to the microtubule destabilizing drug nocodazole and persist throughout the cell cycle. RPGR and RPGRIP1 also co-localize at basal bodies in cells with primary cilia. The C-terminal (C2) domain of RPGR(ORF15) (ORF15(C2)) is highly conserved across 13 mammalian species, suggesting that it is a functionally important domain. Using matrix-assisted laser desorption ionization time-of-flight mas…

CentrioleFluorescent Antibody TechniqueMicechemistry.chemical_compoundChlorocebus aethiopsGuanine Nucleotide Exchange FactorsProtein IsoformsBasal bodyConserved SequenceGenetics (clinical)CentriolesGlutathione Transferaseintegumentary systemNuclear ProteinsExonsGeneral MedicineRetinitis pigmentosa GTPase regulatorImmunohistochemistryNocodazoleCOS CellsNucleophosminCell NucleolusRecombinant Fusion ProteinsMolecular Sequence DataBiologyOpen Reading FramesMicrotubuleTwo-Hybrid System TechniquesGeneticsAnimalsHumansAmino Acid SequenceEye ProteinsMolecular BiologyNucleophosminSequence Homology Amino AcidProteinsPrecipitin TestsMolecular biologyeye diseasesProtein Structure TertiaryMice Inbred C57BLCytoskeletal ProteinschemistryCentrosomeCytoplasmSpectrometry Mass Matrix-Assisted Laser Desorption-IonizationMutationCattleHeLa CellsHuman Molecular Genetics
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