|Ca(2+)-induced permeability transition can be observed even in yeast mitochondria under optimized experimental conditions.|
Yamada A, Yamamoto T, Yoshimura Y, Gouda S, Kawashima S, Yamazaki N, Yamashita K, Kataoka M, Nagata T, Terada H, Pfeiffer DR, Shinohara Y
Biochim Biophys Acta (2009) 1787: 1486-91.
Category: calcium, mitochondria, mitochondria-transport ¤ Added: Oct 05, 2009 ¤ Rating: ◊◊
Yeast mitochondria have generally been believed not to undergo the permeability transition (PT) by the accumulation of Ca(2+) within the mitochondrial matrix, unlike mammalian mitochondria. However, the reason why the yeast PT is not induced by Ca(2+) has remained obscure. In this study, we examined in detail the effects of Ca(2+) on yeast mitochondria under various conditions. As a result, we discovered that the PT could be induced even in yeast mitochondria by externally added Ca(2+) under optimized experimental conditions. The 2 essential parameters for proper observation of the PT-inducing effects of Ca(2+) were the concentrations of the respiratory substrate and that of inorganic phosphate (Pi) in the incubation medium. The yeast mitochondrial PT induced by Ca(2+) was found to be insensitive to cyclosporin A and suppressed in the presence of a high concentration of Pi. Furthermore, when the PT was induced in yeast mitochondria by Ca(2+), the release of cytochrome c from mitochondria was also observed.