Selective uptake of cytosolic, peroxisomal, and plasma membrane proteins into the yeast lysosome for degradation
Selective uptake of cytosolic, peroxisomal, and plasma membrane proteins into the yeast lysosome for degradation
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DOI：
10.1074/jbc.271.17.9934
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发表时间：
1996-04-26
影响因子：
4.8
通讯作者：
Hamamoto, S
中科院分区：
文献类型：
--
作者：
Chiang, HL;Schekman, R;Hamamoto, S
当葡萄糖匮乏的细胞补充葡萄糖时，关键的糖异生酶果糖 -1,6 - 二磷酸酶（FBPase）会从细胞质被选择性地靶向运输到酵母溶酶体（液泡）进行降解。葡萄糖诱导的FBPase靶向液泡进行降解的过程在多种代谢条件下生长的细胞中都会发生。免疫电子显微镜研究表明，液泡对FBPase的摄取部分是由自噬过程介导的。FBPase可以在液泡膜上以及膜内陷部位被发现。此外，FBPase与不同形式的囊泡相关联，这些囊泡被诱导在液泡内积累。我们已经确定过氧化物酶体是在细胞补充葡萄糖时被运输到液泡进行降解的细胞器。超微结构研究表明，过氧化物酶体通过自噬过程被液泡吞噬，导致整个细胞器在液泡中被破坏。此外，半乳糖转运蛋白（Gal2p）也会从质膜被运输到液泡进行降解以响应葡萄糖。Gal2p通过内吞途径被运输到液泡，因为受体介导的内吞作用有缺陷的突变体无法响应葡萄糖降解Gal2p。
When glucose-starved cells are replenished with glucose, the key gluconeogenic enzyme, fructose-1,6-bisphosphatase (FBPase), is selectively targeted from the cytosol to the yeast lysosome (vacuole) for degradation, The glucose-induced targeting of FBPase to the vacuole for degradation occurs in cells grown under a variety of metabolic conditions. Immunoelectron microscopic studies demonstrate that the uptake of FBPase by the vacuole is mediated in part by an autophagic process, FBPase can be found on the vacuolar membrane and also at the sites of membrane invaginations, Furthermore, FBPase is associated with different forms of vesicles, which are induced to accumulate inside the vacuole, We have identified peroxisomes as the organelles that are delivered to the vacuole for degradation when cells are replenished with glucose, Ultrastructural studies indicate that peroxisomes are engulfed by the vacuole by an autophagic process, leading to the destruction of whole organelles in the vacuole. Furthermore, the galactose transporter (Gal2p) is also delivered from the plasma membrane to the vacuole for degradation in response to glucose. Gal2p is delivered to the vacuole through the endocytic pathway, as mutants defective in receptor-mediated endocytosis fail to degrade Gal2p in response to glucose.