A Rab5 GTPase module is important for autophagosome closure
| العنوان: | A Rab5 GTPase module is important for autophagosome closure |
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| المؤلفون: | Yong Chen, Fan Zhou, Zulin Wu, Zhanna Lipatova, Weiming You, Zhiping Xie, Shenshen Zou, Xiaolong Zhu, Wenjing Li, Jie Cheng, Dan Sun, Nava Segev, Yongheng Liang, Yi Ting Zhou, Xiaoxia Cong, Yutao Liu, Qunli Li, Valeriya Gyurkovska, Rui Li |
| المصدر: | PLoS Genetics, Vol 13, Iss 9, p e1007020 (2017) PLoS Genetics |
| بيانات النشر: | Public Library of Science (PLoS), 2017. |
| سنة النشر: | 2017 |
| مصطلحات موضوعية: | 0301 basic medicine, Autophagosome, Cancer Research, Hydrolases, Endocytic cycle, Autophagy-Related Proteins, GTPase, QH426-470, Biochemistry, Phosphatidylinositol 3-Kinases, Fluorescence Microscopy, Genetics (clinical), Microscopy, Cell Death, Kinase, Light Microscopy, Eukaryota, Proteases, Endocytosis, Cell biology, Enzymes, Protein Transport, medicine.anatomical_structure, Cell Processes, Cellular Structures and Organelles, Research Article, Saccharomyces cerevisiae Proteins, Endosome, Autophagic Cell Death, Endosomes, Saccharomyces cerevisiae, Biology, Research and Analysis Methods, 03 medical and health sciences, Lysosome, medicine, Autophagy, Genetics, Vesicles, Molecular Biology, Ecology, Evolution, Behavior and Systematics, rab5 GTP-Binding Proteins, Autophagosomes, Organisms, Fungi, Biology and Life Sciences, Proteins, Cell Biology, Yeast, Guanosine Triphosphatase, 030104 developmental biology, rab GTP-Binding Proteins, Vacuoles, Enzymology, Rab, Lysosomes |
| الوصف: | In the conserved autophagy pathway, the double-membrane autophagosome (AP) engulfs cellular components to be delivered for degradation in the lysosome. While only sealed AP can productively fuse with the lysosome, the molecular mechanism of AP closure is currently unknown. Rab GTPases, which regulate all intracellular trafficking pathways in eukaryotes, also regulate autophagy. Rabs function in GTPase modules together with their activators and downstream effectors. In yeast, an autophagy-specific Ypt1 GTPase module, together with a set of autophagy-related proteins (Atgs) and a phosphatidylinositol-3-phosphate (PI3P) kinase, regulates AP formation. Fusion of APs and endosomes with the vacuole (the yeast lysosome) requires the Ypt7 GTPase module. We have previously shown that the Rab5-related Vps21, within its endocytic GTPase module, regulates autophagy. However, it was not clear which autophagy step it regulates. Here, we show that this module, which includes the Vps9 activator, the Rab5-related Vps21, the CORVET tethering complex, and the Pep12 SNARE, functions after AP expansion and before AP closure. Whereas APs are not formed in mutant cells depleted for Atgs, sealed APs accumulate in cells depleted for the Ypt7 GTPase module members. Importantly, depletion of individual members of the Vps21 module results in a novel phenotype: accumulation of unsealed APs. In addition, we show that Vps21-regulated AP closure precedes another AP maturation step, the previously reported PI3P phosphatase-dependent Atg dissociation. Our results delineate three successive steps in the autophagy pathway regulated by Rabs, Ypt1, Vps21 and Ypt7, and provide the first insight into the upstream regulation of AP closure. Author summary In autophagy, a cellular recycling pathway, the double-membrane autophagosome (AP) engulfs excess or damaged cargo and delivers it for degradation in the lysosome for the reuse of its building blocks. While plenty of information is currently available regarding AP formation, expansion and fusion, not much is known about the regulation of AP closure, which is required for fusion of APs with the lysosome. Here, we use yeast genetics to characterize a novel mutant phenotype, accumulation of unsealed APs, and identify a role for the Rab5-related Vps21 GTPase in this process. Rab GTPases function in modules that include upstream activators and downstream effectors. We have previously shown that the same Vps21 module that regulates endocytosis also plays a role in autophagy. Using single and double mutant analyses, we find that this module is important for AP closure. Moreover, we delineate three Rab GTPase-regulated steps in the autophagy pathway: AP formation, closure, and fusion, which are regulated by Ypt1, Vps21 and Ypt7, respectively. This study provides the first insight into the mechanism of the elusive process of AP closure. |
| اللغة: | English |
| تدمد: | 1553-7404 1553-7390 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d0bef356536ed628bba11d5dba899c51Test https://doaj.org/article/c18c3b7a623e42bba1a6abfa803f5825Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....d0bef356536ed628bba11d5dba899c51 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15537404 15537390 |
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