Centers & Labs

Global Research Cluster

Glycometabolome Team

Team Leader: Tadashi Suzuki (D.Sci.)
Tadashi  Suzuki(D.Sci.)

Peptide:N-glycanase (PNGase) releases N-glycans from glycoproteins/glycopeptides. The cytoplasmic PNGases, ubiquitously found throughout eukaryotes, are now widely recognized as a component implicated in the ERAD (ER-associated degradation) process, which constitute one of the quality control machineries for newly synthesized misfolded glycoproteins exported out of the ER lumen. While the biosynthetic pathway for N-glycans has been clarified in detail, the catabolic pathway for the "free" N-glycans released by the cytoplasmic PNGase remains largrely unknown. Although this "non-lysosomal" metabolic path for N-glycan may represent one of the very basic biological phenomena in eukaryotes, there are still many more enzymes/transporters that remains to be identified.. We are currently trying to identify other players involved in this process through collaboration with Max Planck Institute, and also taking a number of approaches to analyze the physiological importance of this non-lysosomal metabolic pathway.

Main Research Field

Biology & Biochemistry

Related Research Fields

Molecular Biology & Genetics / Microbiology

Research Subjects

  • Mechanism of free N-glycan catabolic pathway
  • Functional role of cytoplasmic PNGase in ERAD
  • Evolutional Diversion of the function of cytoplasmic PNGase

Selected Publications

  1. Harada, Y., Nakajima, K., Masahara-Negishi, Y., Freeze, H. H., Angata, T., Taniguchi, N., and Suzuki, T.:
    "Metabolically programmed quality control system for dolichol-linked oligosaccharides."
    Proc. Natl. Acad. Sci. USA 110, 19366-19371 (2013)
  2. Harada, Y., Buser, R., Ngwa, E. M., Hirayama, H., Aebi, M., and Suzuki, T.:
    "Eukaryotic oligosaccharyltransferase generates free oligosaccharides during N-glycosylation."
    J. Biol. Chem. 288, 32673-32684 (2013)
  3. Seino, J., Wang, L., Harada, Y., Huang, C., Ishii, K., Mizushima, N., and Suzuki, T.:
    "Basal autophagy is required for the efficient catabolism of sialyl oligosaccharides."
    J. Biol. Chem. 288, 26898-26907 (2013)
  4. Wang, L., and Suzuki, T.:
    "Dual functions for cytosolic alpha-mannosidase (Man2C1): its downregulation causes mitochondria-dependent apotosis independently of it's alpha-mannosidase activity."
    J. Biol. Chem. 288, 11887-11896 (2013)
  5. Haga, Y., Ishii, K., Hibino, K., Sako, Y., Ito, Y., Taniguchi, N., and Suzuki, T.:
    "Visualizing specific protein glycoforms by transmembrane fluorescence energy transfer."
    Nature Communications 3, 907 (2012)
  6. Masahara-Negishi, Y.*., and Hosomi, A.*., Della Mea, M., Serafini-Fracassini, D., and Suzuki, T.;
    "A plant peptide:N-glycanase orthologue facilitates glycoprotein ER-associated degradation in yeast."
    Biiochim. Biophys. Acta 1820, 1457-1462 (2012) (*: equally contributed)
  7. Haga, Y., Ishii, K., and Suzuki, T.;
    "N-glycan is essential for stability and intracellular trafficking of glucose transporter, GLUT4."
    J. Biol. Chem. 286, 31320-31327 (2011)
  8. Hirayama, H., and Suzuki, T.;
    "Metabolism of free oligosaccharides is facilitated in the och1 mutant of Saccharomyces cerevisiae."
    Glycobiology 21, 1341-1348 (2011)
  9. Hosomi, A., Tanabe, K., Hirayama, H., Kim, I., Rao, H., and Suzuki, T..:
    "Identification of an Htm1 (EDEM)-dependent, Mns1-independent endoplasmic reticulum-associated degradation (ERAD) pathway in Saccharomyces cerevisiae. Application of a novel assay for glycoprotein ERAD."
    J. Biol. Chem. 285, 24324-24334 (2010)
  10. Hirayama, H., Seino, J., Kitajima, T., Jigami, Y., and Suzuki, T.:
    "Free oligosaccharides to monitor glycoprotein endoplasmic reticulum-associated degradation in Saccharomyces cerevisiae."
    J. Biol. Chem. 285, 12390-12404 (2010)

Lab Members

Principal Investigator

Tadashi Suzuki
Team Leader

Core Members

Akira Hosomi
Contract Researcher
Hiroto Hirayama
Contract Researcher
Yoichiro Harada
Postdoctoral Researcher
Haruhiko Fujihira
Postdoctoral Researcher
Yoshimi Haga
Postdoctoral Researcher
Chengcheng Huang
International Program Associate
Tanim Jabid Hossain
International Program Associate
Haruna Tomotake
Student Trainee
Junichi Seino
Technical Staff I
Yuki Negishi
Technical Staff I
Kotoko Ueno
Part-timer 2
Yae Tsuchiya
Part-timer 2
Tsugiyo Matsuda
Part-timer 2
Sayako Iida
Part-timer 2
Yumiko Suenaga
Part-timer 2

Contact information

2-1 Hirosawa, Wako, Saitama 351-0198, Japan

Email: tsuzuki_gm [at]

Recent Research Results

January 20, 2015: Press Release
Insights into a rare genetic disease
November 8, 2013: RIKEN RESEARCH
In search of a sugar’s secrets