A subfraction of the yeast endoplasmic reticulum associates with the plasma membrane and has a high capacity to synthesize lipids
A subfraction of the yeast endoplasmic reticulum associates with the plasma membrane and has a high capacity to synthesize lipids
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DOI：
10.1046/j.1432-1327.2001.02116.x
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发表时间：
2001-04-01
期刊：
影响因子：
--
通讯作者：
Daum, G
中科院分区：
文献类型：
--
作者：
Pichler, H;Gaigg, B;Daum, G
荧光和电子显微镜显示，酿酒酵母内质网的大部分位于细胞内细胞器，即线粒体和质膜附近。在此，我们报道了与质膜密切相关的内质网亚组分的分离和鉴定。该膜具有高合成磷脂酰丝氨酸和磷脂酰肌醇的能力。因此，PAM使人联想到MAM，一种酵母的线粒体相关膜组分[Gaigg，B.，Simbeni，R.，Hrastnik，C.，Paltauf，F.&Daum，G.(1995)Biochim。生物群落。虽然PAM中的磷脂酰丝氨酸合成酶和磷脂酰肌醇合成酶的比活性是MAM的几倍，但在大宗内质网中也是如此。此外，角鲨烯合成酶(Erg9p)、角鲨烯环氧酶(Erg1p)和甾醇Delta(24)-甲基转移酶(Erg6p)等参与麦角甾醇生物合成的酶在PAM中高度富含。讨论了PAM在脂质供应到质膜中的可能作用。
Large parts of the endoplasmic reticulum of the yeast, Saccharomyces cerevisiae, are located close to intracellular organelles, i.e. mitochondria and the plasma membrane, as shown by fluorescence and electron microscopy. Here we report the isolation and characterization of the subfraction of the endoplasmic reticulum that is closely associated with the plasma membrane. This plasma membrane associated membrane (PAM) is characterized by its high capacity to synthesize phosphatidylserine and phosphatidylinositol. As such, PAM is reminiscent of MAM, a mitochondria associated membrane fraction of the yeast [Gaigg, B., Simbeni, R., Hrastnik, C., Paltauf, F. & Daum, G. (1995) Biochim. Biophys. Acta 1234, 214-220], although the specific activity of phosphatidylserine synthase and phosphatidylinositol synthase in PAM exceeds several-fold the activity in MAM and also in the bulk endoplasmic reticulum. In addition, several enzymes involved in ergosterol biosynthesis, namely squalene synthase (Erg9p), squalene epoxidase (Erg1p) and sterol Delta (24)-methyltransferase (Erg6p), are highly enriched in PAM. A possible role of PAM in the supply of lipids to the plasma membrane is discussed.