Vesicle-associated membrane protein of Arabidopsis suppresses Bax-induced apoptosis in yeast downstream of oxidative burst.
Programmed cell death (PCD) in many systems is controlled by relative amounts of the apoptosis-regulating proteins Bax and Bcl-2 through homo- or heterodimerization. Here we show that Bax-induced PCD of yeast was suppressed by transformation with a vesicle-associated membrane protein from Arabidopsis (AtVAMP), which was isolated by screening a cDNA expression library against sugar-induced cell death in yeast. AtVAMP expression blocked Bax-induced PCD downstream of oxidative burst. AtVAMP also prevented H(2)O(2)-induced apoptosis in yeast and in Arabidopsis cells. Reduced oxidation of lipids and plasma membrane proteins was detected in the AtVAMP-transformed yeast, suggesting improved membrane repair. Inhibition of intracellular vesicle trafficking by brefeldin A induced apoptosis from a sublethal concentration of H(2)O(2). No protection occurred by overexpression of the yeast homolog SCN2. However, efficient suppression of yeast PCD occurred by expression of a chimeric gene, composed of the conserved domains from yeast, fused to the variable N-terminal domain from Arabidopsis, resulting in exchange of the proline-rich N-terminal domain of SCN2 with a proline-poor Arabidopsis sequence. Our results suggest that intracellular vesicle traffic can regulate execution of apoptosis by affecting the rate of membrane recycling and that the proline-rich N-terminal domain of VAMP inhibited this process.
Levine
A
A
Department of Plant Sciences, The Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904, Israel. alexl@mail.ls.huji.ac.il
Belenghi
B
B
Damari-Weisler
H
H
Granot
D
D
D017209:Apoptosis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000502:physiology*; D001483:Base Sequence; D017931:DNA Primers; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008565:Membrane Proteins / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors* / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2; D050683:R-SNARE Proteins; D017382:Reactive Oxygen Species; D016897:Respiratory Burst; D013050:Spectrometry, Fluorescence; D051028:bcl-2-Associated X Protein
D029681:Arabidopsis Proteins; D017931:DNA Primers; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D050683:R-SNARE Proteins; D017382:Reactive Oxygen Species; C121241:VAMP7 protein, human; D051028:bcl-2-Associated X Protein; D006861:Hydrogen Peroxide