Ubiquitination of Glycoproteins in the Cytosol

  • Tadashi Tai


The secretory proteins (membrane proteins, secretion proteins, and lysosomal enzymes) that are synthesized in the ribosome are translocated into the endoplasmic reticulum (ER). These nascent proteins are subjected to modification as the mature glycoproteins by the attachment of carbohydrates and move through the ER via the Golgi complex to their final destinations. The carbohydrate portions of glycoconjugates are implicated in many biological functions and are used as specific markers for cells. They are mainly expressed on the outside of cells. Carbohydrates, however, play an important role in the inside of cells (Helenius and Aebi 2001). N-linked glycoproteins are subjected to the quality control of glycoproteins through which aberrant proteins are distinguished from properly folded proteins and retained in the ER compartment. The quality control system includes the calnexin-calreticulin cycle, a unique chaperone system (Parodi 2000). Here, the author describes briefly the identification of N-glycan-binding proteins for E3 ubiquitin ligases and their perspectives in basic science as well as in clinical medicine.


Ubiquitin Ligase Ubiquitin Proteasome System Quality Control System Ubiquitin System Nascent Protein 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Helenius A, Aebi M (2001) Intracellular functions of N-linked glycans. Science 291:2364–2369PubMedCrossRefGoogle Scholar
  2. Hershko A, Ciechanover A (1998) The ubiquitin system. Annu Rev Biochem 67:425–479PubMedCrossRefGoogle Scholar
  3. Ilyn GP, Serandour AL, Pigeon C, Rialland M, Glaise D, Guguen-Guillouzo C (2002) A new subfamily of structurally related human F-box proteins. Gene 296:11–20CrossRefGoogle Scholar
  4. Parodi AJ (2000) Protein glycosylation and its role in protein folding. Annu Rev Biochem 69:69–93PubMedCrossRefGoogle Scholar
  5. Tai T (2006) Identification of N-glycan-binding proteins for E3 ubiquitin ligases. Methods Enzymol 415:20–30PubMedCrossRefGoogle Scholar

Copyright information

© Springer 2008

Authors and Affiliations

  • Tadashi Tai
    • 1
  1. 1.Central Research LaboratoriesSeikagaku CorporationTokyoJapan

Personalised recommendations