Two Beclin 1-binding proteins, Atg14L and Rubicon, reciprocally regulate autophagy at different stages.
Beclin 1, a protein essential for autophagy, binds to hVps34/Class III phosphatidylinositol-3-kinase and UVRAG. Here, we have identified two Beclin 1 associated proteins, Atg14L and Rubicon. Atg14L and UVRAG bind to Beclin 1 in a mutually exclusive manner, whereas Rubicon binds only to a subpopulation of UVRAG complexes; thus, three different Beclin 1 complexes exist. GFP-Atg14L localized to the isolation membrane and autophagosome, as well as to the ER and unknown puncta. Knockout of Atg14L in mouse ES cells caused a defect in autophagosome formation. GFP-Rubicon was localized at the endosome/lysosome. Knockdown of Rubicon caused enhancement of autophagy, especially at the maturation step, as well as enhancement of endocytic trafficking. These data suggest that the Beclin 1-hVps34 complex functions in two different steps of autophagy by altering the subunit composition.
Pubmed ID: 19270696 RIS Download
Adaptor Proteins, Vesicular Transport | Animals | Apoptosis Regulatory Proteins | Autophagy | Cell Line, Tumor | Endocytosis | Green Fluorescent Proteins | Humans | Membrane Proteins | Mice | Microtubule-Associated Proteins | Multiprotein Complexes | Phagosomes | Protein Binding | Protein Processing, Post-Translational | RNA, Small Interfering | Recombinant Fusion Proteins