Beclin 1 self-association is independent of autophagy induction by amino acid deprivation and rapamycin treatment

• Published in: Journal of cellular biochemistry Vol. 110; no. 5; pp. 1262 - 1271
• Main Authors: Adi-Harel, Shelly, Erlich, Shlomit, Schmukler, Eran, Cohen-Kedar, Sarit, Segev, Oshik, Mizrachy, Liat, Hirsch, Joel A., Pinkas-Kramarski, Ronit
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.08.2010
• Subjects: Amino Acids - metabolism; Amino Acids - pharmacology; Animals; Antibiotics, Antineoplastic - pharmacology; Apoptosis Regulatory Proteins - chemistry; Apoptosis Regulatory Proteins - genetics; Apoptosis Regulatory Proteins - metabolism; autophagy; Autophagy - drug effects; bcl-X Protein - metabolism; Beclin 1; Binding Sites - genetics; Cell Line; Cell Line, Tumor; Cercopithecus aethiops; COS Cells; Glutathione Transferase - genetics; Glutathione Transferase - metabolism; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Humans; Immunoblotting; Immunoprecipitation; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - metabolism; oligomerization; Phosphatidylinositol 3-Kinases - metabolism; Protein Binding; Protein Multimerization; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Sirolimus - pharmacology; Transfection; Tumor Suppressor Proteins - metabolism; UVRAG; vps34
• ISSN: 0730-2312; 1097-4644
• DOI: 10.1002/jcb.22642

Autophagy, a process of self‐digestion of cellular constituents, regulates the balance between protein synthesis and protein degradation. Beclin 1 represents an important component of the autophagic machinery. It interacts with proteins that positively regulate autophagy, such as Vps34, UVRAG, and Ambra1, as well as with anti‐apoptotic proteins such as Bcl‐2 via its BH3‐like domain to negatively regulate autophagy. Thus, Beclin 1 interactions with several proteins may regulate autophagy. To identify novel Beclin 1 interacting proteins, we utilized a GST‐Beclin 1 fusion protein. Using mass spectroscopic analysis, we identified Beclin 1 as a protein that interacts with GST‐Beclin 1. Further examination by cross linking and co‐immunoprecipitation experiments confirmed that Beclin 1 self‐interacts and that the coiled coil and the N‐terminal region of Beclin 1 contribute to its oligomerization. Importantly, overexpression of vps34, UVRAG, or Bcl‐xL, had no effect on Beclin 1 self‐interaction. Moreover, this self‐interaction was independent of autophagy induction by amino acid deprivation or rapamycin treatment. These results suggest that full‐length Beclin 1 is a stable oligomer under various conditions. Such an oligomer may provide a platform for further protein–protein interactions. J. Cell. Biochem. 110: 1262–1271, 2010. Published 2010 Wiley‐Liss, Inc.