Cytoplasmic peptide:N-glycanase removes N-glycans on a carboxypeptidase mutant in Saccharomyces cerevisiae.
Cytoplasmic peptide:N-glycanase removes N-glycans on a carboxypeptidase mutant in Saccharomyces cerevisiae.
复制标题
细胞质肽：N-聚糖酶可去除酿酒酵母中羧肽酶突变体上的 N-聚糖。
DOI：
10.1016/j.bbagen.2014.12.008
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Akira Hosomi and Tadashi Suzuki
中科院分区：
文献类型：
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作者：
Akira Hosomi and Tadashi Suzuki
背景内质网相关降解（ERAD）是内质网中错误折叠或不正确组装的蛋白质降解的一条途径。胞浆肽：N-聚糖酶（PNGase）是一种去糖基化酶，在ERAD过程中从错误折叠的糖蛋白中清除N-聚糖。酵母羧肽酶Y（CPY*）的突变形式是一种ERAD模型底物，已在酵母中进行了广泛研究。虽然在缺乏胞质PNGase的酵母细胞中CPY* 的降解延迟，（酵母中的Png 1）的ERAD酶活性明显，但尚未检测到PNGase对CPY* 的体内作用。在N-和C-末端都带有表位标签，并检查了在具有受损蛋白酶体活性的酵母细胞中观察到的降解中间体。完整CPY* 及其降解中间体的介导的去糖基化是明显的。CPY* 的主要内切蛋白水解反应发生在氨基酸400和404之间。结论在ERAD过程中，PNGase确实从CPY* 释放N-聚糖。
BackgroundEndoplasmic reticulum (ER)-associated degradation (ERAD) is a pathway by which misfolded or improperly assembled proteins in the ER are directed to degradation. The cytoplasmic peptide:N-glycanase (PNGase) is a deglycosylating enzyme that cleavesN-glycans from misfolded glycoproteins during the ERAD process. The mutant form of yeast carboxypeptidase Y (CPY*) is an ERAD model substrate that has been extensively studied in yeast. While a delay in the degradation of CPY* in yeast cells lacking the cytoplasmic PNGase (Png1 in yeast) was evident, thein vivoaction of PNGase on CPY* has not been detected.MethodsWe constructed new ERAD substrates derived from CPY*, bearing epitope tags at both N- and C-termini and examined the degradation intermediates observed in yeast cells with compromised proteasome activity.ResultsThe occurrence of the PNGase-mediated deglycosylation of intact CPY* and its degradation intermediates was evident. A major endoproteolytic reaction on CPY* appears to occur between amino acid 400 and 404.ConclusionsThe findings reported herein clearly indicate that PNGase indeed releasesN-glycans from CPY* during the ERAD processin vivo.General SignificanceThis report implies that the PNGase-mediated deglycosylation during the ERAD process may occur more abundantly than currently envisaged.