Laboratories
Glycometabolome Team
Tadashi SUZUKI
Team Leader
Tadashi SUZUKI (D.Sci.)
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Research Areas

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, and also taking a number of approaches to analyze the physiological importance of this non-lysosomal metabolic pathway.

Research Subject

  1. Mechanism of free N-glycan catabolic pathway
  2. Functional role of cytoplasmic PNGase in ERAD
  3. Evolutional Diversion of the function of cytoplasmic PNGase

Related links

  1. RIKEN Advanced Science Institute Website_Laboratories PageNew Window

Press release

May 31, 2010
Diversity discovered in mechanisms for degrading poorly-formed abnormal glycoproteins
May 11, 2010
New function for degrading poorly-formed proteins discovered in PNGase
February 18, 2010
New catabolic pathway proposed for the decomposition of abnormal glycoproteins

RIKEN RESEARCH

December 02,2011
It takes a sugar to catch a sugar
A single sugar molecule plays an outsized role in helping a glucose-transporting protein respond promptly to insulin signals New Window
April 30,2010
Sweet surprises
By characterizing the sugar content of cells, researchers have begun to reconstruct important 'quality control' mechanisms for protein production New Window

List of Selected Publications

  1. 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.
  2. Hirayama, H., and Suzuki, T.:
    "Metabolism of free oligosaccharides is facilitated in the och1 mutant of Saccharomyces cerevisiae. "
    Glycobiology 21, 1341-1348 (2011)
  3. Kato, A.*, Wang, L., Ishii, K., Seino, J., Asano, N., and Suzuki, T.:
    "Calystegine B3 as a specific inhibitor for cytoplasmic alpha-mannosidase, Man2C1."
    J. Biochem. 149, 415-422 (2011)
  4. 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)
  5. Funakoshi, Y., Negishi, Y., Gergen, J. P., Seino, J., Ishii, K., Lennarz, W.J., Matsuo, I., Ito, Y., Taniguchi, N., and Suzuki, T.:
    "Evidence for an essential deglycosylation-independent activity of PNGase in Drosophila melanogaster."
    PLoS One, 5, e10545 (2010)
  6. 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)
  7. Maerz, S., Funakoshi, Y., Negishi, Y., Suzuki, T., and Seiler, S.:
    "The Neurospora peptide:N-glycanase ortholog PNG1 is essential for cell polarity despite its lack of enzymatic activity."
    J. Biol. Chem. 285, 2326-2332 (2010)
  8. Haga, Y., Totani, K., Ito, Y., and Suzuki, T.:
    "Establishment of a real-time analytical method for free oligosaccharide transport from the ER to the cytosol."
    Glycobiology 19, 987-994 (2009)
  9. Funakoshi, Y and Suzuki, T.:
    "Glycobiology in the cytosol: the bitter side of a sweet world."
    Biochim. Biophys. Acta 1790, 81-94 (2009)
  10. Suzuki, T., Matsuo, I., Totani, K., Funayama, S., Seino, J., Taniguchi, N., Ito, Y., and Hase, S.:
    "Dual-gradient HPLC for identification of cytosolic high mannose-type free glycans."
    Anal. Biochem. 381, 224-232 (2008)

Members

Principal Investigator

Tadashi SUZUKI
Team Leader

Postdoctoral Fellow

Akira HOSOMI
Postdoctoral Researcher
Hiroto HIRAYAMA
Postdoctoral Researcher
Li WANG
Postdoctoral Researcher
Yoichiro HARADA
Postdoctoral Researcher
Yoshimi HAGA
Visiting Researcher

Student Trainee

Chengcheng HUANG
International Program Associate

Technical Assistant

Junichi SEINO
Technical Staff I
Yuki NEGISHI
Technical Staff I

Others

Kotoko UENO
Part-timer 2
Yae TSUCHIYA
Part-timer 2
Tsugiyo MATSUDA
Part-timer 2