14-3-3 inhibits Bad-induced cell death through interaction with serine-136.
14-3-3 proteins are a family of multifunctional phosphoserine binding molecules that can serve as effectors of survival signaling. Understanding the molecular basis for the prosurvival effect of 14-3-3 may lead to the development of agents useful in the treatment of disorders involving dysregulated apoptosis. One target of 14-3-3 is the proapoptotic Bcl-2 family member Bad. Serine phosphorylation of Bad is associated with 14-3-3 binding and inhibition of Bad-induced cell death, but the relative contributions of the three known phosphorylation sites to 14-3-3 binding have not been established. Here we demonstrate that S136 of Bad is vital for 14-3-3 interaction, but S112 seems to be dispensable. 14-3-3/Bad interaction was strictly dependent on the presence of phosphorylated S136 in vitro, in yeast, and in mammalian cells. However, mutation of S112 did not affect 14-3-3 binding. The death caused by wild-type and S112A Bad, but not that caused by S136A Bad, could be almost completely abrogated by 14-3-3. These data support a critical role for 14-3-3 in regulating Bad proapoptotic activity. The effect of 14-3-3 on Bad is controlled largely by phosphorylation of S136, whereas S112 may represent a 14-3-3-independent pathway.
Masters
S C
SC
Graduate Program in Molecular and Systems Pharmacology, Emory University School of Medicine, Atlanta, Georgia, USA.
Yang
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H
Datta
S R
SR
Greenberg
M E
ME
Fu
H
H
D048948:14-3-3 Proteins; D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D001665:Binding Sites; D019556:COS Cells; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D000939:Epitopes; D006367:HeLa Cells; D006801:Humans; D009154:Mutation; D012694:Serine / Q000235:genetics / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000378:metabolism*; D051025:bcl-Associated Death Protein
D048948:14-3-3 Proteins; C494819:BAD protein, human; D002352:Carrier Proteins; D000939:Epitopes; D051025:bcl-Associated Death Protein; D012694:Serine; D014446:Tyrosine 3-Monooxygenase