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Chikashi Toyoshima

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Chikashi Toyoshima
Born (1954-07-17) July 17, 1954 (age 70)
Akita, Japan
CitizenshipJapan
Alma materUniversity of Tokyo
Known forCalcium ATPase
AwardsGregori Aminoff Prize (2016)
Scientific career
FieldsBiophysics
Institutions
Websitewww.iam.u-tokyo.ac.jp/StrBiol/en/

Chikashi Toyoshima (Japanese: 豊島 近, Hepburn: Toyoshima Chikashi; born July 17, 1954) is a Japanese biophysicist,[1] a professor at the University of Tokyo and a Foreign Associate of the National Academy of Sciences in the United States.[2] His research focuses on two proteins: the Ca2+ ATPase, and the Na+/ K+-ATPase.[3] Toyoshima's research about Ca2+ ATPase started in 1989. He and his colleagues obtained the world's first series of images of Ca2+ ATPase at the atomic level.[4] He has determined the crystal structures of ten intermediates of Ca2+ ATPase via X-ray crystallography, cryogenic electron microscopy (cryo-EM), among other methods. Toyoshima and Poul Nissen were awarded the Gregori Aminoff Prize in 2016 by The Royal Swedish Academy of Sciences for their fundamental contributions to understanding the structural basis for ATP-driven translocation of ions across membranes.[5]

Early life and education

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Toyoshima was born in Honjō in the prefecture of Akita, Japan. Toyoshima and his elder brother worked on science experiments at home with their mother.[6] In 1973, he was admitted to the University of Tokyo. He studied regular physics, biochemistry, and botany during his first two years at the university. In the middle of his third year, he visited Setsuro Ebashi's laboratory, which used electron microscopes. He received his undergraduate degree in 1978. For his master’s and doctoral research, Toyoshima focused on the microscopy of thin muscle filaments and myosin heads under the supervision of Setsuro Ebashi. Then in 1983, he completed his doctoral degree.[1][4]

Career

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In 1984, Toyoshima became a research associate at the University of Tokyo. Two years later, he took a postdoctoral position at the laboratory of biophysicist with Nigel Unwin at Stanford University. Under Unwin, Toyoshima worked to develop mathematical methods for disentangling the superimposed information from a projection image or electron micrograph of a tubular structure.

In 1988, Toyoshima followed Unwin to the Medical Research Council's Laboratory of Molecular Biology, where he met and collaborated with biophysicist David Stokes, who was also studying the Ca2+ ATPase.

After moving back to Japan in 1989, he joined the Frontier Research Program at RIKEN as a research scientist. He joined the Tokyo Institute of Technology as an associate professor in 1990. In 1994, Toyoshima was offered a faculty position at the University of Tokyo, where he is currently a professor at the Center for Structural Biology of Challenging Proteins within the Institute of Molecular and Cellular Bio-sciences.[1][3][4]

Research

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Early in his research career, Toyoshima worked on "3 dimensional image analysis of muscle thin filaments decorated by Myosin heads" as an electron microscopist in the Department of Physics at the University of Tokyo.[7] He later conducted research on the acetylcholine receptor after studying cryo-EM in Nigel Unwin's laboratory in 1986. There, he developed a new algorithm to untangle the superimposed images obtained from the cryo-EM. In doing so, he reconstructed a 3D structure of an ion channel at 17 Å resolution.[8] This was the first 3D reconstruction of this ion channel.[3] Soon afterward, the same method was applied to reconstruct the 3D structure of the Ca2+ ATPase with help from David Stokes. Toyoshima and Stokes published their analysis of the structure of this protein in Nature in 1993.[9]

After returning to Japan, Toyoshima continued to focus on the structure of the Ca2+-ATPase. Toyoshima obtained and photographed large crystals of the Ca2+ ATPase in their first state, the E1·2Ca2+ by combining X-ray crystallography and the crystallization methods for electron microscopy. He published the first high-resolution images of P-type ATPases in 2000.[10]

As of 2023, he has determined the crystal structures of the Ca2+ ATPase in ten different states by X-ray crystallography, covering roughly the entire reaction cycle. He also extended his research to the Na+, K+-ATPase[11] and has developed a methodology for electron crystallography of ultra-thin 3 dimensional protein crystals.[12]

Awards

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References

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  1. ^ a b c d "Researchmap".
  2. ^ "Member directory". NATIONAL ACADEMY OF SCIENCES.
  3. ^ a b c Chikashi, Toyoshima (24 March 2016). "The road to understanding an ion pump". Physica Scripta. 91 (4): 042501. Bibcode:2016PhyS...91d2501T. doi:10.1088/0031-8949/91/4/042501. S2CID 124756962.
  4. ^ a b c Nuzzo, Regina (31 January 2006). "Profile of Chikashi Toyoshima". Proceedings of the National Academy of Sciences of the United States of America. 103 (5): 1165–7. Bibcode:2006PNAS..103.1165N. doi:10.1073/pnas.0508495103. PMC 1360550. PMID 16434474.
  5. ^ a b "Gregori Aminoff Prize 2016". Aminoff Prize Committee. 10 September 2015.
  6. ^ Chikashi, Toyoshima (18 August 2008). "Conversations with History". University of California Television.
  7. ^ Chikashi, Toyoshima; Takeyuki, Wakabayashi (5 September 1979). "Three Dimensional Image Analysis of the Complex of Thin Filaments and Myosin Molecules from Skeletal Muscle I.Tilt Angle of Myosin Subfragment-1 in the Rigor Complex". oxfordjournals. Archived from the original on 1 November 2016.
  8. ^ Chikashi, Toyoshima; Nigel, Unwin (17 November 1988). "Ion channel of acetylcholine receptor reconstructed from images of postsynaptic membranes". Nature. 336 (6196): 247–50. Bibcode:1988Natur.336..247T. doi:10.1038/336247a0. PMID 2461515. S2CID 4335410.
  9. ^ Chikashi, Toyoshima; Sasabe, H; Stokes, DL (1 April 1993). "Three-dimensional cryo-electron microscopy of the calcium ion pump in the sarcoplasmic reticulum membrane". Nature. 362 (6419): 467–71. Bibcode:1993Natur.362..469T. doi:10.1038/362469a0. PMID 8385269. S2CID 4262700.
  10. ^ Chikashi, Toyoshima; Nakasako, M; Hiromi, Nomura; Haruo, Ogawa (8 June 2000). "Crystal structure of the calcium pump of sarcoplasmic reticulum at 2.6 Å resolution". Nature. 405 (6787): 647–55. Bibcode:2000Natur.405..647T. doi:10.1038/35015017. PMID 10864315. S2CID 4316039.
  11. ^ Haruo, Ogawa; Chikashi, Toyoshima (10 December 2002). "Homology modeling of the cation binding sites of Na+,K+-ATPase". PNAS. 99 (25): 15977–82. Bibcode:2002PNAS...9915977O. doi:10.1073/pnas.202622299. PMC 138550. PMID 12461183.
  12. ^ Koji, Yonekura; Kazuyuki, Kato; Mitsuo, Ogasawara; Masahiro, Tomita; Chikashi, Toyoshima (17 March 2015). "Electron crystallography of ultrathin 3D protein crystals: Atomic model with charges". PNAS. 112 (11): 3368–73. Bibcode:2015PNAS..112.3368Y. doi:10.1073/pnas.1500724112. PMC 4372003. PMID 25730881.
  13. ^ "「長大な時間」思いはせ 豊島近さん 構造生物学者". Asahi Shimbun. January 2010.
  14. ^ "第11回（平成23年度）山崎貞一賞 バイオサイエンス・バイオテクノロジー分野". Foundation for Promotion of Material Science and Technology of Japan. September 2011.
  15. ^ "平成２７年春の褒章受章者名簿". Cabinet Office,Government of Japan. Mar 2015.
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