Abstract
Autophagy is an intracellular bulk protein degradation system. Beclin is known to be involved in this process; however, its role is unclear. In this study, we showed that Beclin was co-immunoprecipitated with phosphatidylinositol (PtdIns) 3-kinase, which is also required for autophagy, suggesting that Beclin is a component of the PtdIns 3-kinase complex. Quantitative analyses using a cross-linker showed that all Beclin forms a complex with PtdIns 3-kinase, whereas approximately 50% of PtdIns 3-kinase remains free from Beclin. Indirect immunofluorescence microscopy demonstrated that the majority of Beclin and PtdIns 3-kinase localize to the trans-Golgi network (TGN). Some PtdIns 3-kinase is also distributed in the late endosome. These results suggest that Beclin and PtdIns 3-kinase control autophagy as a complex at the TGN.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Androstadienes / pharmacology
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Animals
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Apoptosis Regulatory Proteins
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Beclin-1
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Cross-Linking Reagents / pharmacology
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Dose-Response Relationship, Drug
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Electrophoresis, Polyacrylamide Gel
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Endosomes / metabolism
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Enzyme Inhibitors / pharmacology
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Fluorescent Antibody Technique, Indirect
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HeLa Cells
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Humans
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Lysosomes / metabolism
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Membrane Proteins
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Mice
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Octoxynol / pharmacology
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Phosphatidylinositol 3-Kinases / chemistry*
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Phosphatidylinositol 3-Kinases / metabolism
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Precipitin Tests
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Proteins / chemistry*
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Proteins / metabolism
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Rats
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Subcellular Fractions / metabolism
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Tumor Cells, Cultured
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Wortmannin
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trans-Golgi Network / metabolism*
Substances
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Androstadienes
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Apoptosis Regulatory Proteins
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BECN1 protein, human
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Beclin-1
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Becn1 protein, mouse
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Cross-Linking Reagents
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Enzyme Inhibitors
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Membrane Proteins
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Proteins
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Octoxynol
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Phosphatidylinositol 3-Kinases
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Wortmannin