The Plant Cell · 2003 · 256 citations · 55 references
Life SciencesPlant BiologyPlant SciencesApoptosisPlant Cell BiologyPlant Molecular BiologyApoptosis ModulationApoptosis RegulationApoptotic SignalingBcl-2 Family ProteinsCell DeathProgrammed Cell DeathCell Death RegulatorsCell Growth RegulationCoiled-coil ScaffoldsPro-apoptotic Bax ActivationProgrammed Cell Death Under StressReactive Oxygen Species GenerationSalicylic Acid Treatment
Overexpression of plant Bax Inhibitor-1 (BI-1) was able to suppress Bax-mediated cell death in yeast and Arabidopsis. Here, we demonstrate that reactive oxygen species production induced by the ectopic expression of Bax was insensitive to the coexpression of AtBI-1. Similarly, H2O2- or salicylic acid-mediated cell death also was suppressed in tobacco BY-2 cells overexpressing AtBI-1. To define the functional domain of AtBI-1 as a cell death suppressor, a truncated series of the AtBI-1 protein was analyzed in yeast possessing a galactose-inducible mammalian Bax. The results showed that DeltaC-AtBI-1 (with the C-terminal 14 amino acids deleted) lost the ability to sustain cell growth. Furthermore, a mutant protein in which the C-terminal seven amino acid residues of AtBI-1 were replaced with others lacking a coiled-coil structure failed to inhibit cell death, suggesting that the C-terminal region is essential for the inhibition of cell death. We also noted that the C-terminal hydrophilic region was interchangeable between animal and plant Bax inhibitors.
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