Inhibition of autophagy in mitotic animal cells |
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Authors: | Eskelinen Eeva-Liisa Prescott Alan R Cooper Jennifer Brachmann Saskia M Wang Lijun Tang Xiuwen Backer Jonathan M Lucocq John M |
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Institution: | Centre for High Resolution Imaging and Processing,;Division of Cell Biology and Immunology,;Division of Molecular Physiology, and;Division of Cell Signaling, MSI/WTB Complex, University of Dundee, School of Life Sciences, Dundee DD1 5EH, Scotland, UK;Division of Signal Transduction, Beth Israel Deaconess Medical Center, Harvard Institutes of Medicine, Boston, MA 02115, USA;Institut für Biochemie, Freie Universität Berlin, D-14195 Berlin, GermanyDepartment of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA;University of Kiel, Institute of Biochemistry, Olshausenstr. 40, D-24098 Kiel, Germany |
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Abstract: | In nutrient-deprived cells autophagy recycles cytoplasmic constituents by engulfing and degrading them in membrane-bound autophagic vacuoles. The regulation of autophagic vacuole formation is poorly understood, but here we show this process is under strict cell-cycle control in cultured animal cells. We found strong inhibition of autophagic vacuole accumulation in nocodazole-arrested pseudo-prometaphase cells, and also in metaphase and anaphase cells generated on release from the nocodazole arrest. Autophagic vacuoles reappeared after closure of the nuclear envelope in telophase/G1. Treatment with phosphoinositide 3(PI3)-kinase inhibitors wortmannin, LY294002 and 3-methyladenine (known to inhibit the autophagic response in interphase cells) rescued autophagy in mitotic cells without inducing reassembly of vesiculated ER and Golgi compartments. The autophagy induced in mitotic cells was inhibited by amino acids, and the resulting autophagosomes contained proteins LC3 and Lamp1, known to be associated with autophagosomes in interphase cells. The mitotic inhibition of autophagy was not relieved by rapamycin treatment or in PDK1–/– embryonic stem cells, by microinjection of inhibitory antibodies against the class III PI3 kinase VPS34, or in cell lines lacking the p85 regulatory subunits of class IA PI3 kinases. Our results show that autophagy is under strict mitotic control and indicate a novel role for phosphoinositide 3-kinases or other wortmannin/LY294002-sensitive kinases in mitotic membrane traffic regulation . |
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Keywords: | autophagy LY294002 3-methyladenine mitosis p85 phosphoinositide 3-kinases VPS34 wortmannin |
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