Pmt-mediated O mannosylation stabilizes an essential component of the secretory apparatus, Sec20p, in Candida albicans

被引：24

作者：

Weber, Y ^{[1
]}

Prill, SKH ^{[1
]}

Ernst, JF ^{[1
]}

机构：

[1] Univ Dusseldorf, Inst Mikrobiol, D-40225 Dusseldorf, Germany

来源：

EUKARYOTIC CELL | 2004年 / 3卷 / 05期

关键词：

D O I：

10.1128/EC.3.5.1164-1168.2004

中图分类号：

Q93 [微生物学];

学科分类号：

071005 ; 100705 ;

摘要：

Sec20p is an essential endoplasmic reticulum (ER) membrane protein in yeasts, functioning as a tSNARE component in retrograde vesicle traffic. We show that Sec20p in the human fungal pathogen Candida albicans is extensively O mannosylated by protein mannosyltransferases (Pmt proteins). Surprisingly, Sec20p occurs at wild-type levels in a pmt6 mutant but at very low levels in pmt1 and pmt4 mutants and also after replacement of specific Ser/Thr residues in the lumenal domain of Sec20p. Pulse-chase experiments revealed rapid degradation of unmodified Sec20p (38.6 kDa) following its biosynthesis, while the stable O-glycosylated form (50 kDa) was not formed in a pmt1 mutant. These results suggest a novel function of O mannosylation in eukaryotes, in that modification by specific Pmt proteins will prevent degradation of ER-resident membrane proteins via ER-associated degradation or a proteasome-independent pathway.

引用

页码：1164 / 1168

页数：5

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