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 (Dyca1), cytochrome c (Dcyc1,7) and both (Dcyc1,7Dyca1) were compared for AA-PCD occurrence, hydrogen peroxide (H2O2) production and caspase activity. AA-PCD occurs in Dcyc1,7 and Dcyc1,7Dyca1 cells slower than in wt, but similar to that in Dyca1 cells, in which no cytochrome c release occurs. Both H2O2 production and caspase activation occur in these cells with early and extra-activation in Dcyc1,7 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.