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Chemical‐Synthesis‐Based Approach to Glycoprotein Functions in the Endoplasmic Reticulum
Author(s) -
Ito Yukishige,
Kajihara Yasuhiro,
Takeda Yoichi
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202004158
Subject(s) - calnexin , endoplasmic reticulum , glycoprotein , calreticulin , glycan , mannose , microbiology and biotechnology , biochemistry , golgi apparatus , chemistry , glycosylation , glucosyltransferase , biology , enzyme
The introduction of Asn‐linked glycans to nascent polypeptides occurs in the lumen of the endoplasmic reticulum of eukaryotic cells. After the removal of specific sugar residues, glycoproteins acquire signals in the glycoprotein quality control (GPQC) system and enter the folding cycle composed of lectin‐chaperones calnexin (CNX) and calreticulin (CRT), glucosidase II (G‐II), and UDP‐Glc:glycoprotein glucosyltransferase (UGGT). G‐II initiates glycoproteins’ entry and exit from the cycle, and UGGT serves as the “folding sensor”. This account summarizes our effort to analyze the properties of enzymes and lectins that play important roles in GPQC, especially those involved in the CNX/CRT cycle. To commence our study, general methods for the synthesis of high‐mannose‐type glycans and glycoproteins were established. Based on these, various substrates to analyze components of the GPQC were created, and properties of CRT, G‐II, and UGGT have been clarified.