The Ca(2+)-transport system of yeast (Endomyces magnusii) mitochondria: independent pathways for Ca(2+) uptake and release.
Some features of the Ca(2+)-transport system in mitochondria of the yeast Endomyces magnusii are considered. The Ca(2+) uniporter was shown to be specifically activated by low concentrations of physiological modulators such as ADP, NADH, spermine, and Ca(2+) itself. The Na(+)-independent system responsible for Ca(2+) release from Ca(2+)-preloaded yeast mitochondria was characterized. The rate of the Ca(2+) release was proportional to the Ca(2+) load, insensitive to cyclosporin A and to Na(+), inhibited by La(3+), TPP(+), P(i), and nigericin, while being activated by spermine. We conclude that Ca(2+) release from preloaded E. magnusii yeast mitochondria is mediated by a Na(+)-independent pathway, very similar to that in mitochondria from nonexcitable mammalian tissues. A scheme describing an arrangement of the Ca(2+) transport system of yeast mitochondria is proposed.
Deryabina
Y I
YI
Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, 117071 Russia. inbio@online.ru
Zvyagilskaya
R A
RA
D000935:Antifungal Agents / Q000494:pharmacology; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism* / Q000493:pharmacokinetics; D016572:Cyclosporine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D007700:Kinetics; D007811:Lanthanum / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism*; D008954:Models, Biological; D009243:NAD / Q000378:metabolism; D009550:Nigericin / Q000494:pharmacology; D009861:Onium Compounds / Q000494:pharmacology; D009943:Organophosphorus Compounds / Q000494:pharmacology; D010710:Phosphates / Q000494:pharmacology; D004718:Saccharomycetales / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology; D013053:Spectrophotometry; D013096:Spermine / Q000494:pharmacology
D000935:Antifungal Agents; D007202:Indicators and Reagents; D007476:Ionophores; D009861:Onium Compounds; D009943:Organophosphorus Compounds; D010710:Phosphates; D009243:NAD; D013096:Spermine; D007811:Lanthanum; D016572:Cyclosporine; D012964:Sodium; D009550:Nigericin; D002118:Calcium; C013289:tetraphenylphosphonium