The medial-Golgi ion pump Pmr1 supplies the yeast secretory pathway with Ca2+ and Mn2+ required for glycosylation, sorting, and endoplasmic reticulum associated protein degradation
The medial-Golgi ion pump Pmr1 supplies the yeast secretory pathway with Ca2+ and Mn2+ required for glycosylation, sorting, and endoplasmic reticulum associated protein degradation
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DOI：
10.1091/mbc.9.5.1149
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发表时间：
1998-05-01
影响因子：
3.3
通讯作者：
Rudolph, HK
中科院分区：
文献类型：
--
作者：
Dürr, G;Strayle, J;Rudolph, HK
位于高尔基体内侧的酵母Ca ~（2+）腺苷三磷酸酶Pmr 1参与细胞内Ca ~（2+）和Mn ~（2+）离子的转运。我们在这里表明，除了Mn 2+极大地消除了缺陷的pmr 1突变体的N-连接和O-连接的蛋白质糖基化。相比之下，羧肽酶Y（CpY）的液泡的准确分选需要足够的供应腔内Ca 2+。最值得注意的是，pmr 1突变体也不能降解CpY*，一个错误折叠的可溶性内质网蛋白，并显示类似的突变体的表型缺陷的应激反应错误折叠的内质网蛋白。pmr 1突变体在Ca 2+缺乏培养基上的生长抑制通过表达其他Ca 2+泵来克服，包括来自兔的SERCA型Ca 2+腺苷三磷酸酶，或通过Vps 10，一种引导非天然管腔蛋白到液泡的分选受体。我们的分析证实了Pmr 1在Ca 2+和Mn 2+转运中的双重功能，并确定了这种分泌途径泵在内质网相关过程中的新作用。
The yeast Ca2+ adenosine triphosphatase Pmr1, located in medial-Golgi, has been implicated in intracellular transport of Ca2+ and Mn2+ ions. We show here that addition of Mn2+ greatly alleviates defects of pmr1 mutants in N-linked and O-linked protein glycosylation. In contrast, accurate sorting of carboxypeptidase Y (CpY) to the vacuole requires a sufficient supply of intralumenal Ca2+. Most remarkably, pmr1 mutants are also unable to degrade CpY*, a misfolded soluble endoplasmic reticulum protein, and display phenotypes similar to mutants defective in the stress response to malfolded endoplasmic reticulum proteins. Growth inhibition of pmr1 mutants on Ca2+-deficient media is overcome by expression of other Ca2+ pumps, including a SERCA-type Ca2+ adenosine triphosphatase from rabbit, or by Vps10, a sorting receptor guiding non-native luminal proteins to the vacuole. Our analysis corroborates the dual function of Pmr1 in Ca2+ and Mn2+ transport and establishes a novel role of this secretory pathway pump in endoplasmic reticulum-associated processes.