Interaction of Bcl-2 with the autophagy-related GABAA receptor-associated protein (GABARAP): biophysical characterization and functional implications.
Apoptosis and autophagy are fundamental homeostatic processes in eukaryotic organisms fulfilling essential roles in development and adaptation. Recently, the anti-apoptotic factor Bcl-2 has been reported to also inhibit autophagy, thus establishing a potential link between these pathways, but the mechanistic details are only beginning to emerge. Here we show that Bcl-2 directly binds to the phagophore-associated protein GABARAP. NMR experiments revealed that the interaction critically depends on a three-residue segment (EWD) of Bcl-2 adjacent to the BH4 region, which is anchored to one of the two hydrophobic pockets on the GABARAP molecule. This is at variance with the majority of GABARAP interaction partners identified previously, which occupy both hydrophobic pockets simultaneously. Bcl-2 affinity could also be detected for GEC1, but not for other mammalian Atg8 homologs. Finally, we provide evidence that overexpression of Bcl-2 inhibits lipidation of GABARAP, a key step in autophagosome formation, possibly via competition with the lipid conjugation machinery. These results support the regulatory role of Bcl-2 in autophagy and define GABARAP as a novel interaction partner involved in this intricate connection.
From the Institute of Complex Systems (ICS-6: Structural Biochemistry), Forschungszentrum Jülich, 52425 Jülich and.
Peixiang
P
Ma
Melanie
M
Schwarten
Lars
L
Schneider
Alexandra
A
Boeske
Nadine
N
Henke
Dmitrij
D
Lisak
Stephan
S
Weber
Jeannine
J
Mohrlüder
Matthias
M
Stoldt
Birgit
B
Strodel
Axel
A
Methner
Silke
S
Hoffmann
Oliver H
OH
Weiergräber
Dieter
D
Willbold
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020816:Amino Acid Motifs; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D051017:Apoptosis Regulatory Proteins; D001343:Autophagy / Q000502:physiology*; D002461:Cell Line, Transformed; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D054878:Lipoylation / Q000502:physiology*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051381:Rats
D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; D003598:Cytoskeletal Proteins; C116741:GABARAP protein, human; C480861:GABARAP protein, mouse; C502186:GABARAP protein, rat; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C052617:Bcl2 protein, mouse
Apoptosis; Autophagy; Bcl-2; GABARAP; LC3; Lipidation; NMR; Protein-Protein Interactions