Overexpression of Pex15p, a phosphorylated peroxisomal integral membrane protein required for peroxisome assembly in S-cerevisiae, causes proliferation of the endoplasmic reticulum membrane
Overexpression of Pex15p, a phosphorylated peroxisomal integral membrane protein required for peroxisome assembly in S-cerevisiae, causes proliferation of the endoplasmic reticulum membrane
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DOI：
10.1093/emboj/16.24.7326
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发表时间：
1997-12-15
期刊：
影响因子：
11.4
通讯作者：
Tabak, HF
中科院分区：
文献类型：
--
作者：
Elgersma, Y;Kwast, L;Tabak, HF
我们克隆了酿酒酵母过氧化物酶体生物合成所需的PEX 15。pex 15 δ细胞的特征在于含有PTS 1或PTS 2输入信号的过氧化物酶体基质蛋白的胞质积累，而过氧化物酶体膜蛋白存在于过氧化物酶体残余物中，PEX 15编码磷酸化的完整过氧化物酶体膜蛋白（Pex 15 p）。使用多种体内方法来确定拓扑结构，发现Pex 15 p是尾锚定的II型（N-cyt-C-lumen）过氧化物酶体膜蛋白，在其羧基末端附近具有单个跨膜结构域。Pex 15 p的过表达导致过氧化物酶体组装受损，并引起内质网（ER）膜的深度增殖。如其O-糖基化所证明的，Pex 15 p的内腔羧基末端尾部突出到这些ER膜的内腔中。当Pex 15 p融合到成熟转化酶的N-末端时，还观察到在ER中的内源表达水平的积累，Pex 15 p的C-末端尾区是Pex 15 p靶向过氧化物酶体膜所必需的。此外，Pex 15 p的过氧化物酶体膜靶向信号与该蛋白上的ER靶向信号重叠。这些结果表明Pex 15 p可能通过ER靶向过氧化物酶体，或靶向两种细胞器。
We have cloned PEX15 which is required for peroxisome biogenesis in Saccharomyces cerevisiae. pex15 Delta cells are characterized by the cytosolic accumulation of peroxisomal matrix proteins containing a PTS1 or PTS2 import signal, whereas peroxisomal membrane proteins are present in peroxisomal remnants, PEX15 encodes a phosphorylated, integral peroxisomal membrane protein (Pex15p). Using multiple in vivo methods to determine the topology, Pex15p was found to be a tail-anchored type II (N-cyt-C-lumen) peroxisomal membrane protein with a single transmembrane domain near its carboxy-terminus. Overexpression of Pex15p resulted in impaired peroxisome assembly, and caused profound proliferation of the endoplasmic reticulum (ER) membrane, The lumenal carboxy-terminal tail of Pex15p protrudes into the lumen of these ER membranes, as demonstrated by its O-glycosylation, Accumulation in the ER was also observed at an endogenous expression level when Pex15p was fused to the N-terminus of mature invertase, This resulted in core N-glycosylation of the hybrid protein, The lumenal C-terminal tail of Pex15p is essential for targeting to the peroxisomal membrane, Furthermore, the peroxisomal membrane targeting signal of Pex15p overlaps with an ER targeting signal on this protein, These results indicate that Pex15p may be targeted to peroxisomes via the ER, or to both organelles.