Keiichi Inoue / Associate Professor / Division of Transdisciplinary Sciences
Department of Advanced Materials Science / / Biological Molecular Science, Photobiophysics

Career Summary
2002: Graduated from Department of Chemistry, Faculty of Science, Kobe University
2007-2008: Research Fellow for Young Scientists of JSPS, Department of Chemistry, Kyoto University
2007: Ph.D. in Science from Kyoto University
2007-2009: Research Associate, Chemical Resources Laboratory, Tokyo Institute of Technology
2009-2016: Assistant Professor, Department of Frontier Materials, Nagoya Institute of Technology, Japan
2012-2015: PRESTO Researcher (Research Area: Design and Control of Cellular Functions), JST, Japan
2015-2019: PRESTO Researcher (Research Area: Fully controlled photons and their proactive usage for new era creation (FRONTIER)), JST, Japan
2016-2018: Associate Professor, Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Japan
2018-present: Associate Professor, The Institute for Solid State Physics

Educational Activities
Graduate school: Introduction to Biological Physicochemistry

Research Activities
In order to survive in nature, most living species on the earth use sunlight as an energy source for their biological activity and/or as information to recognize the outer world. Various types of photo-receptive proteins play a central role in this process. In our laboratory, we study the molecular mechanism of their photo-biological functions, mainly photo-receptive membrane protein rhodopsins, with a physicochemical approach based on spectroscopic measurement. We have reported on the molecular mechanisms of light-driven outward Na+ pump rhodopsin, light-driven inward H+ pump rhodopsin, and so on, and we discovered a new family of rhodopsin, Heliorhodopsin, in 2018.
(Top) Microbial rhodopsins with various functions. Bottom-left: Purified protein samples of microbial rhodopsins. Bottom-right: Time-resolved spectroscopy system.
(Top) Microbial rhodopsins with various functions. Bottom-left: Purified protein samples of microbial rhodopsins. Bottom-right: Time-resolved spectroscopy system.

1) P.-A. Bulzu, A.-Ş. Andrei, M. M. Salcher, M. Mehrshad, K. Inoue, H. Kandori, O. Beja, R. Ghai*, and H. L. Banciu (2019), "Lux in Tenebris Lucet: Casting Light on Asgardarchaeota Metabolism in a Sunlit Microoxic Niche", Nature Microbiol., in press ( : Equally contributed).
2) A. Pushkarev, K. Inoue, S. Larom, J. Flores-Uribe, M. Singh, M. Konno, S. Tomida, S. Ito, R. Nakamura, S. P. Tsunoda, A. Philosof, I. Sharon, N. Yutin, E. V. Koonin, H. Kandori*, and O. Beja* (2018), "A Distinct Abundant Group of Microbial Rhodopsins Discovered via Functional Metagenomics", Nature, 558, pp. 595-599 ( : Equally contributed).
3) K. Inoue, S. Ito, Y. Kato, Y. Nomura, M. Shibata, T. Uchihashi, S. P. Tsunoda, and H. Kandori* (2016), "Natural Light-driven Inward Proton Pump", Nature Commun., 7, Article number:13415.
4) K. Inoue, Y. Nomura, and H. Kandori* (2016), "Asymmetric Functional Conversion of Eubacterial Light-driven Ion Pumps", J. Biol. Chem., 291, pp. 9883-9893 (selected in "Highlights of 2016" of J. Biol. Chem.).
5) K. Inoue, M. Konno, R. Abe-Yoshizumi, and H. Kandori* (2015), "The Role of the NDQ-motif in Sodium Pump Rhodopsin", Angew. Chem. Int. Ed., 54, pp. 11536-11539.
6) H. E. Kato, K. Inoue, R. Abe-Yoshizumi, Y. Kato, H. Ono, M. Konno, T. Ishizuka, M. R. Hoque, S. Hososhima, H. Kunitomo, J. Ito, S. Yoshizawa, K. Yamashita, M. Takemoto, T. Nishizawa, R. Taniguchi, K. Kogure, A. D. Maturana, Y. Iino, H. Yawo, R. Ishitani, H. Kandori*, and O. Nureki* (2015), "Structural Basis for Na+ Transport Mechanism by a Light-driven Na+ Pump", Nature, 521, pp. 48-53.
7) K. Inoue, T. Tsukamoto, K. Shimono, Y. Suzuki, S. Miyauchi, S. Hayashi, H. Kandori, and Y. Sudo* (2015), "Converting a Light-driven Proton Pump into a Light-gated Proton Channel", J. Am. Chem. Soc., 137, pp. 3291-3299.
8) K. Inoue, H. Ono, R. Abe-Yoshizumi, S. Yoshizawa, H. Ito, K. Kogure, and H. Kandori* (2013), "A Light-driven Sodium Ion Pump in Marine Bacteria", Nature Commun., 4, Article number:1678.

Other Activities
Japan Society for Molecular Science
The Biophysical Society of Japan
The Chemical Society of Japan
The Spectroscopical Society of Japan
The Photobiology Association of Japan (2017-2019)

Future Plan
We will explore novel types of photo-receptive proteins, mainly rhodopsins, and study the molecular mechanism of the biomolecular function by advanced spectroscopy. Furthermore, we will apply these photo-receptive proteins to optogenetics.

Messages to Students
The recent rapid progress of biological technology, such as next-generation genome analysis, is revealing the presence of billions of biological molecules, particularly proteins, in nature. These molecules possess a complexity and high functionality far exceeding artificial molecules. Elucidating the mechanism at the molecular level not only clarifies the basic principle of biological activity of living organisms but also provides useful knowledge for the developments of new molecular tools and materials. In order to understand complex biomolecules, we need to flexibly utilize not only biology but also a wide range of knowledge such as chemistry, physics, and information science, and to integrate their viewpoints. I hope that students who are interested in such research will enjoy the pleasure of developing this fertile plane of an infinitely expanding scientific world.