Bio:
While pursuing his Ph.D., Takato worked on the identification and functional characterization of blue-light photoreceptor cryptochromes in the fern Adiantum capillus-veneris and the moss Physcomitrella patens with Masamitsu Wada at the National Institute for Basic Biology (NIBB) in Okazaki, Japan. After receiving his Ph.D., Takato joined Steve Kay’s lab at the Scripps Research Institute (TSRI), where he worked on elucidating the molecular mechanisms underlying seasonal (especially day-length dependent) flowering response in Arabidopsis thaliana. Takato joined the faculty of the University of Washington in 2008.
Professional Experience
Assistant Professor, University of Washington, 2008
Associate Research Scientist, UC San Diego, 2007-2008
Assistant Professor of Plant Biology, TSRI, 2007
Staff Scientist, TSRI, 2005-2007
Research Associate, TSRI, 2003-2005
Japan Society for the Promotion of Science (JSPS) Postdoctoral
Fellow for Research Abroad, TSRI, 2001-2003
JSPS Research Fellow, Tokyo Metropolitan University, Japan, 1998-2001
Education
Ph.D., Biology, Tokyo Metropolitan University, Japan, 2001
M.S., Biology, Tokyo Metropolitan University, Japan, 1998
B.S., Biology, Tokyo Metropolitan University, Japan, 1996
Research Interests:
 My general research interest is elucidating the molecular mechanisms by which organisms respond to various environmental changes. Currently, I am interested in studying seasonal and diurnal time-keeping mechanisms. Many organisms possess molecular time-keeping mechanisms called “circadian clocks” to anticipate and prepare for daily changes in the surrounding environment. Organisms often use these clocks to measure changes in day length in order to coordinate their development with the most favorable seasons. The responses induced by day-length changes are referred to as “photoperiodism”. I use the model plant Arabidopsis thaliana to uncover the mechanisms of the plant molecular seasonal calendar.
As shown in the figure, these two Arabidopsis plants were grown for the same length of time under the same experimental conditions except for the day-length regimes. The plant on the left was grown under short day conditions (8 hours light and 16 hours dark, mimicking short winter days), while the one on the right was grown under long day conditions (16 hours light and 8 hours dark, mimicking long summer days). Flowering is induced by long day conditions in Arabidopsis. Because this photoperiodic flowering response is dramatic, I use this response as a physiological readout to study how plants respond to changes in day length.
Photoperiodism is best understood in plants through the study of photoperiodic flowering. In addition, discoveries made in plants have often facilitated additional discoveries in mammals and other systems and this is why I propose to further elucidate the molecular mechanism of photoperiodic flowering in Arabidopsis. In my lab, we use various techniques, such as molecular biology, molecular genetics, biochemistry, cell biology and genomic approaches to study the mechanisms underlying photoperiodism.
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Selected Publications:
Harmon, F.G., Imaizumi, T., and Gray, W.M. (2008) CUL1 regulates TOC1 protein stability in the Arabidopsis circadian clock. Plant J. 55: 568-579
Para, A., Farré, E.M., Imaizumi, T., Pruneda-Paz, J.L., Harmon, F.G., and Kay, S.A. (2007) PRR3 is a vascular regulator of TOC1 stability in the Arabidopsis circadian clock. Plant Cell 19: 3462-3473
Imaizumi, T., Kay, S.A., and Schroeder, J.I. (2007) Circadian rhythms: Daily watch on metabolism. Science 318:1730-1731
Sawa, M., Nusinow, D.A., Kay, S.A., and Imaizumi, T. (2007) FKF1 and GIGANTEA complex formation is required for day-length measurement in Arabidopsis. Science 318:261-265
Imaizumi, T., Schroeder, J.I., and Kay, S.A. (2007) In SYNC: The ins and outs of circadian oscillations in calcium. Sci. STKE pe32
Imaizumi, T., and Kay, S.A. (2006) Photoperiodic control of flowering: not only by coincidence. Trends in Plant Sci. 11:550-558
Imaizumi, T., Schultz T.F., Harmon, F.G., Ho, L.A., and Kay, S.A. (2005) FKF1 F-box protein mediates cyclic degradation of a repressor of CONSTANS in Arabidopsis. Science 309:293-297
Welsh, D.K., Imaizumi, T., and Kay, S.A. (2005) Real-time reporting of circadian-regulated gene expression by luciferase imaging in plants and mammalian cells. Methods Enzymol. 393:269-288
Imaizumi, T., Tran, H.G., Swartz, T.E., Briggs, W.R., and Kay, S.A. (2003) FKF1 is essential for photoperiodic-specific light signaling in Arabidopsis. Nature 426: 302-306
Kawai, H., Kanegae, T., Christensen, S., Kiyosue, T., Sato, Y., Imaizumi, T., Kadota, A., and Wada, M. (2003). Responses of ferns to red light are mediated by an unconventional photoreceptor. Nature 421: 287-290
Imaizumi, T., Kadota, A., Hasebe, M., and Wada, M. (2002). Cryptochrome light signals control development to suppress auxin sensitivity in the moss Physcomitrella patens. Plant Cell 14: 373-386
Imaizumi, T., Kanegae, T., and Wada, M. (2000). Cryptochrome nucleocytoplasmic distribution and gene expression are regulated by light quality in the fern Adiantum capillus-veneris. Plant Cell 12: 81-96
Nozue, K., Kanegae, T., Imaizumi, T., Fukuda, S., Okamoto, H., Yeh, K.C., Lagarias, J.C. and Wada, M. (1998) A phytochrome from the fern Adiantum with features of the putative photoreceptor NPH1. Proc. Natl. Acad. Sci. USA. 95: 15826-15830.
Teaching Interests:
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