Summary of Research Project Results under JSPS FY2001
"Research for the Future Program"

1.Research Institution  Kyushu Institute of Technology
2.Research Area  Integrated Fields
3.Research Field Information on Life Systems
4.Term of Project  FY 1997 ` FY 2001
5.Project Number  97I00101
6.Title of Project  Design and Fabrication of an Interface System for a Life Information Processor and External Environment -Electrophysiological and Biochemical Approach -

7.Project Leader
Name Institution,Department Title of Position
Takeshi Yamakawa Kyushu Inst. of Tech., Graduate School of Life Sci. and Sys. Eng. Professor

8.Core Members

Names Institution,Department Title of Position
Shozo Yasui Kyushu Inst. of Tech., Graduate School of Life Sci. and Sys. Eng. Professor
Tetsuya Yagi Osaka Univ., Graduate School of Eng. Professor
Tatsuya Haga Gakushuin Univ., Institute for Biomolecular Sci. Professor

9.Summary of Research Results

<Electrophysiological Approach>@The adaptation function of the organs of the perception of the bodily function has been investigated by physiological experiments, and the Vision Chip which is based on the knowledge from the experiments has been established. Furthermore, the pattern recognition method and the signal separation method based on the information processing of the bodily function using some artificial neural networks techniques are established.
<Biochemical Approach>@G protein-coupled receptors (GPCRs) are major sensors of cells for extracellular signals and can recognize light, odorants, taste substances, hormones, neurotransmitters and others. We have screened GPCRs from the human genome sequence by taking advantage of the facts that many GPCRs do not have introns and all GPCRs have seven transmembrane segments, and estimated that there are approximately 500 genes for odorant GPCRs and 400-500 genes for other GPCRs in the human genome. GPCRs, after activation by extracellular ligands, activate G protein ƒ¿GDPƒÀY trimer at the intracellular face, which involves exchange of GDP-GTP and dissociation of ƒ¿GDPƒÀY into ƒ¿GTPƒÀY subunits. We have prepared fusion proteins of G protein a subunits with some GPCRs including muscarinic acetylcholine receptors, b adrenergic receptors, and nociceptin receptors, and expressed them in insect cells (Sf9) using baculovirus. Membrane preparations expressing receptor-Ga fusion proteins were shown to recognize ligands for the receptor and to discriminate full-, partial-, inverse-agonists and antagonists by measuring the ligand-induced change in the affinity for GDP. We have prepared fusion proteins with Gi1a or Gsa subunits of novel orphan GPCRs, which we have identified from the human genome sequence, and used them for search of endogenous or surrogate agonists. Receptor-Ga fusion proteins could be used for drug screening and, potentially, as chemical sensors.

10.Key Words

(1)Electrophysiology@(2)Biochemistry@(3)‚nrgans of ‚oerception
(4)AdaptationESelf-organization@(5)Analog Sensing Device@(6)G protein-coupled receptors
(7) @(8)