A5061660473- Neurobiology and Insect Physiology Research
- Photoreceptor and optogenetics research
- Retinal Development and Disorders
- Antioxidant Activity and Oxidative Stress
- Circadian rhythm and melatonin
- Physiological and biochemical adaptations
- Retinoids in leukemia and cellular processes
- Ion Channels and Receptors
- Retinal Diseases and Treatments
- Plant and Biological Electrophysiology Studies
- Hippo pathway signaling and YAP/TAZ
- Aquaculture Nutrition and Growth
- Cellular transport and secretion
- Plant Molecular Biology Research
- Plant Stress Responses and Tolerance
- Herbal Medicine Research Studies
- Bioactive Compounds and Antitumor Agents
University of Hohenheim
2009-2019
University of Freiburg
2004-2009
In animals, successful production of the visual chromophore (11- cis -retinal or derivatives thereof such as 11- -3-hydroxy-retinal) is essential for photoreceptor cell function and survival. These carotenoid-derived compounds must combine with a protein moiety (the opsin) to establish functional pigments. Evidence from culture systems has implicated that retinal pigment epithelium 65 kDa (RPE65) long-sought all- trans retinoid isomerase. RPE65 structurally related nonheme iron oxygenases...
The blind Drosophila mutant ninaD lacks the visual chromophore. Genetic evidence that molecular basis is a defect in carotenoid uptake which causes vitamin A deficiency exists. gene encodes scavenger receptor significantly homologous sequence with mammalian receptors SR-BI (scavenger class B type I) and CD36 (cluster determinant 36), yet NinaD has not been characterized functional detail. Therefore, we established S2 cell culture system for biochemically characterizing products. We show two...
Transient receptor potential (TRP) channels constitute an ancient family of cation that have been found in many eukaryotic organisms from yeast to human. TRP exert a multitude physiological functions ranging Ca2+ homeostasis the kidney pain reception and vision. These are activated by wide range stimuli undergo covalent post-translational modifications affect modulate their subcellular targeting, biophysical properties, or channel gating. include N-linked glycosylation, protein...
In animals, visual pigments are essential for photoreceptor function and survival. These G-protein-coupled receptors consist of a protein moiety (opsin) covalently bound 11-cis-retinylidene chromophore. The chromophore is derived from dietary carotenoids by oxidative cleavage trans-to-cis isomerization double bonds. vertebrates, the necessary chemical transformations catalyzed two distinct but structurally related enzymes, carotenoid oxygenase beta-carotenoid-15,15'-monooxygenase retinoid...
The Drosophila phototransduction cascade terminates in the opening of an ion channel, designated transient receptor potential (TRP). TRP has been shown to become phosphorylated vitro, suggesting regulation channel through posttranslational modification. However, except for one phosphorylation site, Ser982, which was analyzed by functional vivo studies (Popescu, D. C., Ham, A. J., and Shieh, B. H. (2006) J. Neurosci. 26, 8570–8577), nothing is known about role vivo. Here, we report...
Protein phosphorylation plays a cardinal role in regulating cellular processes eukaryotes. Phosphorylation of proteins is controlled by protein kinases and phosphatases. We previously reported the light-dependent Drosophila transient receptor potential (TRP) ion channel at multiple sites. TRP generates upon stimulation photoreceptor cell light. An eye-enriched kinase C (eye-PKC) has been implicated vitro studies. Other phosphatases are elusive. Using phosphospecific antibodies mass...
Drosophila photoreceptors respond to oscillating light of high frequency (∼100 Hz), while the detected maximal is modulated by rearing conditions, thus enabling sensitivity and temporal resolution. However, molecular basis for this adaptive process unclear. Here, we report that dephosphorylation light-activated transient receptor potential (TRP) ion channel at S936 a fast, graded, light-dependent, Ca2+-dependent partially rhodopsin phosphatase retinal degeneration C (RDGC). Electroretinogram...
Drosophila photoreceptors respond to oscillating light of high frequency (∼100 Hz), while increasing the intensity raises maximally detected frequency. Recently, we reported that dephosphorylation light-activated TRP ion channel at S936 is a fast, graded, light-, and Ca2+-dependent process. We further found this process affects detection limit light. Accordingly, transgenic Drosophila, which do not undergo phosphorylation S936-TRP site (trpS936A), revealed short time-interval before...
Drosophila inactivation no afterpotential D (INAD) is a PDZ domain-containing scaffolding protein that tethers components of the phototransduction cascade to form supramolecular signaling complex. Here, we report identification eight INAD phosphorylation sites using mass spectrometry approach. PDZ1, PDZ2, and PDZ4 each harbor one site, three are located in linker region between PDZ1 2, site PDZ2 PDZ3, N-terminal region. Using phosphospecific antibody, found phosphorylated at Thr170/Ser174...
Drosophila retinal degeneration C (RDGC) is the founding member of PPEF family protein phosphatases. RDGC mediates dephosphorylation visual pigment rhodopsin and TRP ion channel. From rdgC locus, three isoforms, termed RDGC-S, -M, -L, with different N-termini are generated. Due to fatty acylation, RDGC-M -L attached plasma membrane while RDGC-S soluble. To assign physiological roles these we constructed flies that express various combinations isoforms. Expression RDGC-L isoform alone did not...