Sac1p mediates the adenosine triphosphate transport into yeast endoplasmic reticulum that is required for protein translocation.
Sac1p mediates the adenosine triphosphate transport into yeast endoplasmic reticulum that is required for protein translocation.
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DOI：
10.1083/jcb.131.6.1377
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发表时间：
1995-12
期刊：
影响因子：
--
通讯作者：
Meyer DI
中科院分区：
文献类型：
--
作者：
Mayinger P;Bankaitis VA;Meyer DI
蛋白质转运进入酵母内质网需要ATP转运进入这个细胞器的内腔。将微粒体ATP转运活性重组到蛋白脂质体中以表征和鉴定转运蛋白。纯化多肽，其部分氨基酸序列证明其与SAC1基因产物的同一性。因此，发现从SAC1基因（sac1 δ）缺失菌株中分离的微粒体膜缺乏ATP转运活性，并且其转运新生前α因子原和前羧肽酶原Y的能力严重受损。从sac1 δ菌株的微粒体膜分离的蛋白质在重组到体外测定系统中时不能刺激ATP转运。当免疫纯化至均一并掺入人工脂质囊泡中时，Sac1p显示出重建ATP转运活性。与ATP在ER腔中实现分泌蛋白的正确折叠的要求一致，sac1 δ菌株显示出在将羧肽酶原Y运输出ER并进入体内高尔基复合体中存在严重缺陷。收集的数据表明Sac1p在将ATP运输到ER腔中的密切作用。
Protein translocation into the yeast endoplasmic reticulum requires the transport of ATP into the lumen of this organelle. Microsomal ATP transport activity was reconstituted into proteoliposomes to characterize and identify the transporter protein. A polypeptide was purified whose partial amino acid sequence demonstrated its identity to the product of the SAC1 gene. Accordingly, microsomal membranes isolated from strains harboring a deletion in the SAC1 gene (sac1 delta) were found to be deficient in ATP-transporting activity as well as severely compromised in their ability to translocate nascent prepro- alpha-factor and preprocarboxypeptidase Y. Proteins isolated from the microsomal membranes of a sac1 delta strain were incapable of stimulating ATP transport when reconstituted into the in vitro assay system. When immunopurified to homogeneity and incorporated into artificial lipid vesicles, Sac1p was shown to reconstitute ATP transport activity. Consistent with the requirement for ATP in the lumen of the ER to achieve the correct folding of secretory proteins, the sac1 delta strain was shown to have a severe defect in transport of procarboxypeptidase Y out of the ER and into the Golgi complex in vivo. The collective data indicate an intimate role for Sac1p in the transport of ATP into the ER lumen.