Beclin-phosphatidylinositol 3-kinase complex functions at the trans-Golgi network.
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.
Kihara
A
A
Department of Cell Biology, National Institute for Basic Biology, Nishigonaka 38, Myodaiji-cho, Okazaki 444-8585, Japan.
Kabeya
Y
Y
Ohsumi
Y
Y
Yoshimori
T
T
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D011992:Endosomes / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019084:Fluorescent Antibody Technique, Indirect; D006367:HeLa Cells; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D008565:Membrane Proteins; D051379:Mice; D017830:Octoxynol / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000737:chemistry* / Q000378:metabolism; D011233:Precipitin Tests; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism; D014407:Tumor Cells, Cultured; D000077191:Wortmannin; D021601:trans-Golgi Network / Q000378:metabolism*
D000730:Androstadienes; D051017:Apoptosis Regulatory Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; C115010:Becn1 protein, mouse; D003432:Cross-Linking Reagents; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D011506:Proteins; D017830:Octoxynol; D019869:Phosphatidylinositol 3-Kinases; D000077191:Wortmannin