Requirement for Neo1p in retrograde transport from the Golgi complex to the endoplasmic reticulum
Requirement for Neo1p in retrograde transport from the Golgi complex to the endoplasmic reticulum
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DOI：
10.1091/mbc.e03-07-0463
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发表时间：
2003-12-01
影响因子：
3.3
通讯作者：
Graham, TR
中科院分区：
文献类型：
--
作者：
Hua, ZL;Graham, TR
酿酒酵母Neo1p是一种必需的P型ATPase，也是Drs2p家族中潜在的氨基磷脂转位酶。我们之前已经发现，Drs2p参与了需要ADP核糖化因子(ARE)和笼蛋白的晚期分泌途径中的蛋白质运输步骤。在这里，我们提出了表位标记的Neo1p定位于内质网(ER)和高尔基复合体的证据，并且是这些细胞器之间逆行运输途径所必需的。利用NEO1的条件等位基因，我们发现Neo1p功能的丧失会导致早期分泌途径中顺行蛋白运输的货物特异性缺陷，并扰乱高尔基复合体的糖基化。Rer1-GFP是一种在COPI和COPII囊泡中的ER和高尔基复合体之间循环的蛋白质，在不允许的温度下被错误地定位到新的1-TS的液泡中。这些表型表明，顺行蛋白转运缺陷是COPI依赖的逆行途径缺陷的次要后果。我们认为顺式高尔基体中脂质不对称性的丧失扰乱了蛋白质逆行转运到内质网。
Neo1p from Saccharomyces cerevisiae is an essential P-type ATPase and potential aminophospholipid translocase (flippase) in the Drs2p family. We have previously implicated Drs2p in protein transport steps in the late secretory pathway requiring ADP-ribosylation factor (ARE) and clathrin. Here, we present evidence that epitope-tagged Neo1p localizes to the endoplasmic reticulum (ER) and Golgi complex and is required for a retrograde transport pathway between these organelles. Using conditional alleles of NEO1, we find that loss of Neo1p function causes cargo-specific defects in anterograde protein transport early in the secretory pathway and perturbs glycosylation in the Golgi complex. Rer1-GFP, a protein that cycles between the ER and Golgi complex in COPI and COPII vesicles, is mislocalized to the vacuole in neo1-ts at the nonpermissive temperature. These phenotypes suggest that the anterograde protein transport defect is a secondary consequence of a defect in a COPI-dependent retrograde pathway. We propose that loss of lipid asymmetry in the cis Golgi perturbs retrograde protein transport to the ER.