Researcher Information



Understand fundamental principle and interpretation of life phenomena in the chemical points of view

Department of Chemistry, Organic and Biological Chemistry


"Function, structure, and regulation of tumor suppressor protein p53 and related factors"
"Ser/Thr Phosphatase PPM1 Family and development of inhibitors for PPM1D oncoprotein"
"Structure control of nanomaterials by peptide self-assembly and oligomerization"

FieldBiological Chemistry, Functional Biochemistry, Structural Biochemistry, Molecular Biology, Cellular Biology, Protein Science, Peptide Science
KeywordTumor Supperessor Protein, Cell Cycle, Differentiation, Canser, Evolution, Oligomerization, Phosphatase, Phosphorylation/Dephospharylation, Anticancer drug, Bionanomaterials

Introduction of Research

Function, oligomerization, regulation and evolution of the tumor suppressor protein p53
The tumor suppressor protein p53 is activated in response to a wide variety of cellular stresses including DNA damages and starvation in order to maintain “genomic integrity” through induction of cell cycle arrest and apoptosis. The tetramer formation of p53 is essential for its functions. The TP53 gene, which encodes p53, is the most frequently mutated gene in human malignant tumors. In our laboratory, we are pursuing detailed research on the regulatory mechanisms of the function and tetramerization for p53 by post-translational modification and interaction with other factors. We are also interested in evolution of the p53/p63/p73 family.

Function and substrate recognition by phosphatase PPM family phosphatases
Phosphorylation by kinases and dephosphorylation by phosphatases is the most important post-translational modification of proteins in the regulation for cellular responses. PPM family proteins are Mg2+/Mn2+-dependent Ser/Thr phosphatases involved in various cellular responses. Aberrant functions of PPM family cause failures in phosphorylation/dephosphorylation signaling, resulted in various illnesses, including cancer, neurological disorders, and metabolic diseases. Our goal is to understand the functions, regulatory mechanisms, and substrate recognition of PPM phosphatases. We are also developing highly potent and specific PPM1D inhibitors as an anti-tumor drug

Nanomaterials via self-assembling biomolecules as structure-controlling elements
Peptides and DNA form distinctive conformations based on their amino acid/nucleotide sequences. We are establishing technology for functionalization and shape control of nanomaterials by using self-assembling biomolecules, including coiled-coil, p53 tetramerization and amyloid peptides, as structural elements.


Representative Achievements

Oligomerization enhances the binding affinity of a silver biomineralization peptide and catalyzes nanostructure formation. Sakaguchi T., Janairo, J. I. B., Lussier-Price M. Wada J., Omichinski J.G., Sakaguchi K. Scientific reports 7: 1400 (2017)
Tetramer Formation of Tumor Suppressor Protein p53: Structure, Function, and Applications. Kamada, R., Toguchi, Y., Nomura, T., Imagawa, T., Sakaguchi, K. Biopolymers, 106, 598 (2016).
PPM1D controls nucleolar formation by up-regulating phosphorylation of nucleophosmin. Kozakai Y., Kamada R., Furuta J., Kiyota Y., Chuman Y., and Sakaguchi K. Scientific reports 6, 33272 (2016)
Formation of Functionalized Nanowires by Control of Self-Assembly Using Multiple Modified Amyloid Peptides. Sakai, H., Watanabe, K., Asanomi, Y., Kobayashi, Y., Chuman, Y., Shi, L., Masuda, T., Wyttenbach, T., Bowers, MT., Uosaki, K., and Sakaguchi, K. Advanced Functional Materials, 23, 4881 (2013).
DNA damage activates p53 through a phosphorylation-acetylation cascade. Sakaguchi, K., Herrera, J.E., Saito, S, Miki, T, Bustin, M., Vassilev, A., Anderson, C.W., and Appella, A. Genes Dev. 12: 2831-2841, 1998.

Related industries

Medicine, Biochemistry
Academic degreePh.D.
Academic background1983 B.Sc. Kyushu University, Fukuoka, Japan,
1986 M.Sc. Kyushu University, Fukuoka, Japan,
1989 Ph.D. Kyushu University, Fukuoka, Japan
1989 Visiting Fellow National Cancer Institute, National Institutes of Health, MD, USA,
1992 Visiting Associate National Cancer Institute, National Institutes of Health, MD, USA,
1997 Staff Scientist Appointed National Cancer Institute, National Institutes of Health, MD, USA,
1999 Staff Scientist National Cancer Institute, National Institutes of Health, MD, USA,
1999 Associate Professor Kyushu University, Fukuoka, Japan,
2003 Professor Hokkaido University, Sapporo, Japan,
Affiliated academic societyThe Japanese Biochemical Society, The Chemical Society of Japan, The Japanese Peptde Society, Japanese Association For Protein Phosphatase Research, Japanese Society for Chemical Biology, American Chemical Society
Room addressScience Building 6 Room 6-5-03

H-index: 55
i10-index: 109
Total citation: 20254
(@Feb. 1, 2019)