Yeast acetic acid-induced programmed cell death can occur without cytochrome c release which requires metacaspase YCA1

To investigate the role of cytochrome c (cyt c) release in yeast acetic acid-induced programmed cell death (AA-PCD), wild type (wt) and cells lacking metacaspase (Delta yca1), cytochrome c (Delta cyc1,7) and both (Delta cyc1,7 Delta yca1) were compared for AA-PCD occurrence, hydrogen peroxide (H2O2) production and caspase activity. AA-PCD occurs in Delta cyc1,7 and Delta cyc1,7 Delta yca1 cells slower than in wt, but similar to that in Delta yca1 cells, in which no cytochrome c release occurs. Both H2O2 production and caspase activation occur in these cells with early and extra-activation in Delta cyc1,7 cells. We conclude that alternative death pathways can be activated in yeast AA-PCD, one dependent on cyt c release, which requires YCA1, and the other(s) independent on it. (C) 2009 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.