Apoptosis in yeast - a monocellular organism exhibits altruistic behaviour

Apoptosis is a highly regulated form of programmed cell death crucial for l ife and health in metazoan animals. Apoptosis is defined by a set of cytolo gical alterations. The recent discovery of these markers in yeast indicates the presence of the basic mechanisms of apoptosis already in unicellular e ukaryotes. Oxygen radicals regulate both mammalian and yeast apoptosis. We suggest that apoptosis originated in unicellular organisms as an altruistic response to severe oxidative damage. Later, cells developed mechanisms to purposely produce reactive oxygen species as a regulator of apoptosis. Yeas t may become an important model to investigate the conserved steps of apopt osis. (C) 2000 Federation of European Biochemical Societies.