{"title":"The biological role of core 1β1-3galactosyltransferase (T-synthase) in mucin-type O-glycosylation in Silkworm, Bombyx mori","authors":"Akihiro Morio , Jae Man Lee , Tsuguru Fujii , Hiroaki Mon , Akitsu Masuda , Kohei Kakino , Jian Xu , Yutaka Banno , Takahiro Kusakabe","doi":"10.1016/j.ibmb.2023.103936","DOIUrl":null,"url":null,"abstract":"<div><p><span>O-glycosylation of secreted and membrane-bound proteins is an important post-translational modification that affects recognition of cell surface receptors, protein folding, and stability. However, despite the importance of </span><em>O-</em><span>linked glycans, their biological functions have not yet been fully elucidated and the synthetic pathway of </span><em>O-</em><span>glycosylation<span> has not been investigated in detail, especially in the silkworm. In this study, we aimed to investigate </span></span><em>O-</em>glycosylation in silkworms by analyzing the overall structural profiles of mucin-type <em>O-</em><span><span>glycans using LC–MS. We found GalNAc or GlcNAc </span>monosaccharide<span> and core 1 disaccharide (Galβ1-3-GalNAcα1-Ser/Thr) were major components of the </span></span><em>O-</em><span>glycan attached to secreted proteins produced in silkworms. Furthermore, we characterized the 1 b1,3-galactosyltransferase (T-synthase) required for synthesis of the core 1 structure, common to many animals. Five transcriptional variants and four protein isoforms<span> were identified in silkworms, and the biological functions of these isoforms were investigated. We found that BmT-synthase isoforms 1 and 2 were localized in the Golgi apparatus in cultured </span></span><em>Bm</em><span><span>N4 cells and functioned both in cultured cells and silkworms. Additionally, a specific functional domain of T-synthase, called the stem domain, was found to be essential for activity and is presumed to be needed for dimer formation and </span>galactosyltransferase activity. Altogether, our results elucidated the </span><em>O</em>-glycan profile and function of T-synthase in the silkworm. Our findings allow the practical comprehension of <em>O-</em><span>glycosylation required for employing silkworms as a productive expression system.</span></p></div>","PeriodicalId":330,"journal":{"name":"Insect Biochemistry and Molecular Biology","volume":null,"pages":null},"PeriodicalIF":3.2000,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Insect Biochemistry and Molecular Biology","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0965174823000309","RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
O-glycosylation of secreted and membrane-bound proteins is an important post-translational modification that affects recognition of cell surface receptors, protein folding, and stability. However, despite the importance of O-linked glycans, their biological functions have not yet been fully elucidated and the synthetic pathway of O-glycosylation has not been investigated in detail, especially in the silkworm. In this study, we aimed to investigate O-glycosylation in silkworms by analyzing the overall structural profiles of mucin-type O-glycans using LC–MS. We found GalNAc or GlcNAc monosaccharide and core 1 disaccharide (Galβ1-3-GalNAcα1-Ser/Thr) were major components of the O-glycan attached to secreted proteins produced in silkworms. Furthermore, we characterized the 1 b1,3-galactosyltransferase (T-synthase) required for synthesis of the core 1 structure, common to many animals. Five transcriptional variants and four protein isoforms were identified in silkworms, and the biological functions of these isoforms were investigated. We found that BmT-synthase isoforms 1 and 2 were localized in the Golgi apparatus in cultured BmN4 cells and functioned both in cultured cells and silkworms. Additionally, a specific functional domain of T-synthase, called the stem domain, was found to be essential for activity and is presumed to be needed for dimer formation and galactosyltransferase activity. Altogether, our results elucidated the O-glycan profile and function of T-synthase in the silkworm. Our findings allow the practical comprehension of O-glycosylation required for employing silkworms as a productive expression system.
期刊介绍:
This international journal publishes original contributions and mini-reviews in the fields of insect biochemistry and insect molecular biology. Main areas of interest are neurochemistry, hormone and pheromone biochemistry, enzymes and metabolism, hormone action and gene regulation, gene characterization and structure, pharmacology, immunology and cell and tissue culture. Papers on the biochemistry and molecular biology of other groups of arthropods are published if of general interest to the readership. Technique papers will be considered for publication if they significantly advance the field of insect biochemistry and molecular biology in the opinion of the Editors and Editorial Board.