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The stem region of α1,6-fucosyltransferase FUT8 is required for multimer formation but not catalytic activity.
Tomida, Seita; Nagae, Masamichi; Kizuka, Yasuhiko.
Afiliação
  • Tomida S; The United Graduate School of Agricultural Science, Gifu University, Gifu, Japan.
  • Nagae M; Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan; Laboratory of Molecular Immunology, Immunology Frontier Research Center (IFReC), Osaka University, Suita, Japan.
  • Kizuka Y; The United Graduate School of Agricultural Science, Gifu University, Gifu, Japan; Institute for Glyco-core Research (iGCORE), Gifu University, Gifu, Japan. Electronic address: kizuka@gifu-u.ac.jp.
J Biol Chem ; 298(12): 102676, 2022 12.
Article em En | MEDLINE | ID: mdl-36336076
Alpha-1,6-fucosyltransferase (FUT8) synthesizes core fucose in N-glycans, which plays critical roles in various physiological processes. FUT8, as with many other glycosyltransferases, is a type-II membrane protein, and its large C-terminal catalytic domain is linked to the FUT8 stem region, which comprises two α-helices. Although the stem regions of several glycosyltransferases are involved in the regulation of Golgi localization, the functions of the FUT8 stem region have not been clarified as yet. Here, we found that the FUT8 stem region is essential for enzyme oligomerization. We expressed FUT8Δstem mutants, in which the stem region was replaced with glycine/serine linkers, in FUT8-KO HEK293 cells. Our immunoprecipitation and native-PAGE analysis showed that FUT8 WT formed a multimer but FUT8Δstem impaired multimer formation in the cells, although the mutants retained specific activity. In addition, the mutant protein had lower steady-state levels, increased endoplasmic reticulum localization, and a shorter half-life than FUT8 WT, suggesting that loss of the stem region destabilized the FUT8 protein. Furthermore, immunoprecipitation analysis of another mutant lacking a part of the stem region revealed that the first helix in the FUT8 stem region is critical for multimer formation. Our findings demonstrated that the FUT8 stem region is essential for multimer formation but not for catalytic activity, providing insights into how the FUT8 protein matures and functions in mammalian cells.
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Polissacarídeos / Fucosiltransferases Idioma: En Ano de publicação: 2022 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Polissacarídeos / Fucosiltransferases Idioma: En Ano de publicação: 2022 Tipo de documento: Article