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1996 Fiscal Year Final Research Report Summary

Molecular mechanism of phototransduction in rhabdomeric photoreceptors.

Research Project

Project/Area Number 07839018
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section時限
Research Field 光生物学
Research InstitutionHyogo College of Medicine

Principal Investigator

SUZUKI Tatsuo  Hyogo College of Medicine, Faculty of Medicine, Assistant Professor, 医学部, 講師 (90068544)

Project Period (FY) 1995 – 1996
KeywordsCell Signaling / Photoreception / Photoreceptor Cell / Rhodopsin / GTP-binding Protein / Phospholipase C
Research Abstract

The object of this research project was to prove the rhodopsin/G-protein/phospholipase C cascade in rhabdomeric photoreceptors. The following results were obtained. 1. The experiments of immunoprecipitation demonstrated that photo-activated rhodopsin formed complex with alpha subunit of Gq and that the complex dissociated in the presence of GTP.2. Reconstitution experiments demonstrated that PLC was acitvated by GTP-bound Gqalpha and not by Gbetagamma.3. GTPgammaS-binding experiments demonstrated that GDP-GTP exchange reaction was very slow in soluble Gqalpha in contrast to extremely rapid one in membrane Gqalpha. The potency of PLC-activation of soluble Gqalpha is a half of that of membrane Gqalpha. 4. The reversible translocation of Gqalpha between membrane and cytosol in response to light was shown in crayfish retina by biochemical and immunocytochemical experiments. The transformation of membrane Gqalpha to soluble Gqalpha was suggested to be due to depalmitoylation of Gqalpha from the results of hydroxyl amine-treatment.
These results showed that rhodopsin/Gq-class G-protein/phospholipase C cascade is the main pathway of phototransduction and suggested that the translocation of Gqalpha is one of the molecular mechanisms of light-adaptation of rhabdomeric photoreceptor cells to regulate photosensitivity.

  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] Suzuki T.: "Phosphatidyl inositol‐phospholipase C in squid retina is activated by stable metarhodopsin viaGTP‐binding protein,Gq." Vision Research. 35. 1011‐1017 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Suzuki T.: "Squid photoreceptor phospholipase C is activated by membrane Gqα but not by soluble Gqα." FEBS Letters.377. 333-337 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Terakita A.: "The invertebrate phototransduction cascade is similar to that of mammalian hormonal receptor system." RIKEN Review. 11. 61-62 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Terakita A.: "Light-modulated subcellular localization of alpha-subunit of GTP‐binding protein Gq in crayfish photoreceptors." Visual Neurosci.13. 539-547 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Suzuki Tatsuo: "Phosphatidyl inositol-phospholipase C in squid retina is activated by stable metarhodopsin via GTP-binding protein, Gq." Vision Research. 35. 1011-1017 (1955)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Suzuki Tatsuo: "Squid photoreceptor phospholipase C is activated by membrane Gqalpha but not by soluble Gqalpha." FEBS Letters. 377. 333-337 (1955)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Terakita Akihisa: "The invertebrate phototransduction cascade is similar to that of mammalian hormonal receptor system." RIKEN Review. 11. 61-62 (1955)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Terakita Akihisa: "Light-modulated subcellular localization of alpha-subunit of GTP-binding protein Gq in crayfish photoreceptors." Visual Neuroscience. 13. 539-547 (1996)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-03-09  

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