Chs7p, a new protein involved in the control of protein export from the endoplasmic reticulum that is specifically engaged in the regulation of chitin synthesis in Saccharomyces cerevisiae.
Chs7p, a new protein involved in the control of protein export from the endoplasmic reticulum that is specifically engaged in the regulation of chitin synthesis in Saccharomyces cerevisiae.
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CHS7P是一种新蛋白，参与控制蛋白质从内质网的输出，该蛋白质专门从事酿酒酵母中几丁质合成的调节。
DOI：
10.1083/jcb.145.6.1153
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发表时间：
1999-06-14
影响因子：
7.8
通讯作者：
Roncero, C
中科院分区：
文献类型：
--
作者：
Trilla, J A;Duran, A;Roncero, C
酿酒酵母 CHS7 基因编码位于内质网的整合膜蛋白，该蛋白通过调节几丁质合酶 III (CSIII) 活性直接参与几丁质合成。在缺乏 CHS7 产物的情况下，Chs3p（而不是其他分泌蛋白）保留在 ER 中，导致 CSIII 活性严重缺陷，从而导致几丁质合成率降低。此外，chs7无效突变体显示出与缺乏几丁质相关的酵母表型：交配效率降低和缺乏壳聚糖子囊孢子层，清楚地表明了Chs7p在整个酿酒酵母生物周期中的功能。 CHS3 过度表达不会导致 CSIII 水平增加，因为过量的 Chs3p 保留在 ER 中。然而，CHS3 和 CHS7 的联合过表达增加了 Chs3p 从 ER 的输出，并且伴随着 CSIII 活性的随之增加，表明 Chs7p 的量是 CSIII 活性的限制因素。因此，当检测到几丁质合成量增加时，CHS7 转录就会增加。这些结果表明 Chs7p 形成了一种新机制的一部分，该机制专门参与 Chs3p 从 ER 的输出，从而参与 CSIII 活性的调节。
The Saccharomyces cerevisiae CHS7 gene encodes an integral membrane protein located in the ER which is directly involved in chitin synthesis through the regulation of chitin synthase III (CSIII) activity. In the absence of CHS7 product, Chs3p, but not other secreted proteins, is retained in the ER, leading to a severe defect in CSIII activity and consequently, to a reduced rate of chitin synthesis. In addition, chs7 null mutants show the yeast phenotypes associated with a lack of chitin: reduced mating efficiency and lack of the chitosan ascospore layer, clear indications of Chs7p function throughout the S. cerevisiae biological cycle. CHS3 overexpression does not lead to increased levels of CSIII because the Chs3p excess is retained in the ER. However, joint overexpression of CHS3 and CHS7 increases the export of Chs3p from the ER and this is accompanied by a concomitant increase in CSIII activity, indicating that the amount of Chs7p is a limiting factor for CSIII activity. Accordingly, CHS7 transcription is increased when elevated amounts of chitin synthesis are detected. These results show that Chs7p forms part of a new mechanism specifically involved in Chs3p export from the ER and consequently, in the regulation of CSIII activity.