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.
Matsunaga
Kohichi
K
Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, Suita, Japan.
Saitoh
Tatsuya
T
Tabata
Keisuke
K
Omori
Hiroko
H
Satoh
Takashi
T
Kurotori
Naoki
N
Maejima
Ikuko
I
Shirahama-Noda
Kanae
K
Ichimura
Tohru
T
Isobe
Toshiaki
T
Akira
Shizuo
S
Noda
Takeshi
T
Yoshimori
Tamotsu
T
D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism*; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D001343:Autophagy; D000071186:Beclin-1; D045744:Cell Line, Tumor; D004705:Endocytosis; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D046912:Multiprotein Complexes / Q000378:metabolism; D010588:Phagosomes / Q000648:ultrastructure; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D034741:RNA, Small Interfering / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D033942:Adaptor Proteins, Vesicular Transport; D051017:Apoptosis Regulatory Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; C477012:MAP1LC3A protein, human; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D046912:Multiprotein Complexes; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins