Medical Research Institute - Department of Life ScienceDivision of Protein Regulation Research



Division for Protein Regulation

Dr. Tasaki’s main interest is how cellular functions are regulated by post-translational modifications of proteins, especially by a ubiquitylation system. Regulated degradation of cellular proteins by the ubiquitin-proteasome system (UPS) mediates a number of functions including cell division, cancer, immune response, embryonic development, gene transcription, and DNA repair. The set of short-lived proteins mediated by UPS yielded a rule, called the N-end rule, which relates in vivo half-life of a protein to the identity of its N-terminal residue. In this pathway, the substrate degradation signal (N-degron) is recognized by the one class of E3 ubiquitin ligases, N-recognins. His previous studies identified the mammalian N-recognin family consisting of UBR1, UBR2, UBR4, and UBR5, which recognize N-degrons through the conserved UBR box. Dr. Tasaki has developed a unique capture system for N-recognins and gene-targeting mice for UBR3 and UBR4. Studies are underway to elucidate the physiological functions of the N-end rule pathway in mammals.
In addition to basic studies on the N-end rule pathway, Dr. Tasaki is also interested in cancer biology. Recent studies revealed that UBR4 is strongly interacted with the E7 oncoprotein from human papillomavirus, the initiation factor of cervical cancers.
Dr. Tasaki’s group is also involved in virology. Using Japanese encephalitis virus, his group is working on identifying the host cellular factor(s) that regulate the viral life cycle.

Contact Information

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Associate Professor

  • TASAKI Takafumi

Research Achievements

Research Activities

  • Tasaki T, Kim ST, Zakrzewska A, Lee BE, Kang MJ, Yoo YD, Cha-Molstad HJ, Hwang J, Soung NK, Sung KS, Kim SH, Nguyen MD, Sun M, Yi EC, Kim BY, Kwon YT. (2013) UBR box N-recognin-4 (UBR4), an N-recognin of the N-end rule pathway, and its role in yolk sac vascular development and autophagy. Proc. Natl. Acad. Sci. USA. 110, 3800-3805
  • Tasaki T, Sriram SM, Park KS, and Kwon YT. (2012) The N-end rule pathway. Ann. Rev. Biochem. 81, 261-289
  • Tasaki T, Zakrzewska A, Dudgeon DD, Jiang Y, Lazo JS, and Kwon YT. (2009) The substrate recognition domains of the N-end rule pathway. J. Biol. Chem. 284, 1884-1895
  • Tasaki T, Sohr R, Xia Z, Hellweg R, Hortnagl H, Varshavsky A, and Kwon YT. (2007) Biochemical and genetic studies of UBR3, a ubiquitin ligase with a function in olfactory and other sensory systems. J. Biol. Chem. 282, 18510-18520
  • Tasaki T, Mulder LC, Iwamatsu A, Lee MJ, Davydov IV, Muesing M, Varshavsky A, and Kwon YT. (2005) A Family of Mammalian E3 Ubiquitin Ligases that contain the UBR box motif and recognize N-degrons. Mol.Cell. Biol. 25, 7120-7136

External Research Funding

  • MEXT Grant-in-Aid for Scientific Research (C) 25430119
  • The Hokkoku Cancer Research Foundation (2012)