2009年7月
The Cytoplasmic Tail of GM3 Synthase Defines Its Subcellular Localization, Stability, and In Vivo Activity
MOLECULAR BIOLOGY OF THE CELL
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- ,
- ,
- 巻
- 20
- 号
- 13
- 開始ページ
- 3088
- 終了ページ
- 3100
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1091/mbc.E08-12-1219
- 出版者・発行元
- AMER SOC CELL BIOLOGY
GM3 synthase (SAT-I) is the primary glycosyltransferase responsible for the biosynthesis of ganglio-series gangliosides. In this study, we identify three isoforms of mouse SAT-I proteins, named M1-SAT-I, M2-SAT-I, and M3-SAT-I, which possess distinct lengths in their NH(2)-terminal cytoplasmic tails. These isoforms are produced by leaky scanning from mRNA variants of mSAT-Ia and mSAT-Ib. M2-SAT-I and M3-SAT-I were found to be localized in the Golgi apparatus, as expected, whereas M1-SAT-I was exclusively found in the endoplasmic reticulum (ER). Specific multiple arginines (R) arranged in an R-based motif, RRXXXXR necessary for ER targeting, were found in the cytoplasmic tail of M1-SAT-I, and in vivo GM3 biosynthesis by M1-SAT-I was very low because of restricted transport to the Golgi apparatus. In addition, M1-SAT-I and M3-SAT-I had a long half-life relative to M2-SAT-I. This is the first report demonstrating the presence of an ER-targeting R-based motif in the cytoplasmic tail of a protein in the mammalian glycosyltransferase family of enzymes. The system, which produces SAT-I isoforms having distinct characteristics, is likely to be of critical importance for the regulation of GM3 biosynthesis under various pathological and physiological conditions.
- リンク情報
- ID情報
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- DOI : 10.1091/mbc.E08-12-1219
- ISSN : 1059-1524
- PubMed ID : 19420140
- Web of Science ID : WOS:000267536400009