The proapoptotic protein Bad binds the amphipathic groove of 14-3-3zeta.
Through interaction with a multitude of target proteins, 14-3-3 proteins participate in the regulation of diverse cellular processes including apoptosis. These 14-3-3-interacting proteins include a proapoptotic Bcl-2 homolog, Bad (Bcl-2/Bcl-XL-associated death promoter). To understand how 14-3-3 interacts with Bad and modulates its function, we have identified structural elements of 14-3-3 necessary for 14-3-3/Bad association. 14-3-3 contains a conserved amphipathic groove that is required for binding to several of its ligands. We used peptides of known binding specificity as competitors to demonstrate that Bad interacts with 14-3-3zeta via its amphipathic groove. More detailed analysis revealed that several conserved residues in the groove, including Lys-49, Val-176, and Leu-220, were critical for Bad interaction. These results were applied to investigations of the ability of 14-3-3 to prevent Bad-induced cell death. When co-expressed with Akt, wild-type 14-3-3 could reduce the ability of Bad to cause death, however 14-3-3zetaK49E, which cannot bind Bad, failed to inhibit Bad. It seems that the amphipathic groove of 14-3-3 represents a general binding site for multiple ligands, raising issues related to competition of ligands for 14-3-3.
Yang
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Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
Masters
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SC
Wang
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H
Fu
H
H
D048948:14-3-3 Proteins; D017209:Apoptosis; D001665:Binding Sites; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D009154:Mutation; D010748:Phosphopeptides / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D015398:Signal Transduction; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000378:metabolism*; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein
D048948:14-3-3 Proteins; C494819:BAD protein, human; C494811:BCL2L1 protein, human; D002352:Carrier Proteins; D010748:Phosphopeptides; D019253:Proto-Oncogene Proteins c-bcl-2; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein; D014446:Tyrosine 3-Monooxygenase