title: Differential interactions between Beclin 1 and Bcl-2 family members.
abstract: Autophagy, a cellular degradation system, promotes both cell death and survival. The interaction between Bcl-2 family proteins and Beclin 1, a Bcl-2 interacting protein that promotes autophagy, can mediate crosstalk between autophagy and apoptosis. We investigated the interaction between anti-and pro-apoptotic Bcl-2 proteins with Beclin 1. Our results show that Beclin 1 directly interacts with Bcl-2, Bcl-x(L), Bcl-w and to a lesser extent with Mcl-1. Beclin 1 does not bind the pro-apoptotic Bcl-2 proteins. The interaction between Beclin 1 and the anti-apoptotic protein Bcl-x(L) was inhibited by BH3-only proteins, but not by multi-domain proteins. Sequence alignment and structural modeling suggest that Beclin 1 contains a putative BH3-like domain which may interact with the hydrophobic grove of Bcl-x(L). Mutation of the Beclin 1 amino acids predicted to mediate this interaction inhibited the association of Beclin 1 with Bcl-x(L). Our results suggest that BH3 only proapoptotic Bcl-2 proteins may modulate the interactions between Bcl-x(L) and Beclin 1.
authors.affiliation: Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel.
authors.forename: Shlomit
authors.initials: S
authors.lastname: Erlich
authors.forename: Liat
authors.initials: L
authors.lastname: Mizrachy
authors.forename: Oshik
authors.initials: O
authors.lastname: Segev
authors.forename: Liora
authors.initials: L
authors.lastname: Lindenboim
authors.forename: Ofir
authors.initials: O
authors.lastname: Zmira
authors.forename: Sheli
authors.initials: S
authors.lastname: Adi-Harel
authors.forename: Joel A
authors.initials: JA
authors.lastname: Hirsch
authors.forename: Reuven
authors.initials: R
authors.lastname: Stein
authors.forename: Ronit
authors.initials: R
authors.lastname: Pinkas-Kramarski
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001343:Autophagy; D051023:BH3 Interacting Domain Death Agonist Protein / Q000378:metabolism; D000071186:Beclin-1; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000166:cytology; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000378:metabolism*; D010957:Plasmids; D017434:Protein Structure, Tertiary / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D051028:bcl-2-Associated X Protein / Q000378:metabolism*; D051020:bcl-X Protein / Q000737:chemistry / Q000378:metabolism*
chemical_list: D051017:Apoptosis Regulatory Proteins; C491073:BCL2L2 protein, human; C491997:BECN1 protein, human; D051023:BH3 Interacting Domain Death Agonist Protein; D000071186:Beclin-1; D008565:Membrane Proteins; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011993:Recombinant Fusion Proteins; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D005982:Glutathione Transferase