Beclin 1 self-association is independent of autophagy induction by amino acid deprivation and rapamycin treatment.
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-x(L), 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.
Adi-Harel
Shelly
S
Department of Neurobiology, Tel-Aviv University, Ramat-Aviv 69978, Israel.
Erlich
Shlomit
S
Schmukler
Eran
E
Cohen-Kedar
Sarit
S
Segev
Oshik
O
Mizrachy
Liat
L
Hirsch
Joel A
JA
Pinkas-Kramarski
Ronit
R
D000596:Amino Acids / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D051017:Apoptosis Regulatory Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001343:Autophagy / Q000187:drug effects*; D000071186:Beclin-1; D001665:Binding Sites / Q000235:genetics; D019556:COS Cells; D002460:Cell Line; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011485:Protein Binding; D055503:Protein Multimerization; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020123:Sirolimus / Q000494:pharmacology*; D014162:Transfection; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D051020:bcl-X Protein / Q000378:metabolism
D000596:Amino Acids; D000903:Antibiotics, Antineoplastic; D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; D005982:Glutathione Transferase; D049452:Green Fluorescent Proteins; D008565:Membrane Proteins; D019869:Phosphatidylinositol 3-Kinases; D011993:Recombinant Fusion Proteins; D020123:Sirolimus; D025521:Tumor Suppressor Proteins; D051020:bcl-X Protein; C491997:BECN1 protein, human; C408122:UVRAG protein, human