title: Mitochondrial Ca2+ sequestration and precipitation revisited.
abstract: The ability of mitochondria to sequester and retain divalent cations in the form of precipitates consisting of organic and inorganic moieties has been known for decades. Of these cations, Ca(2+) has emerged as a major player in both signal transduction and cell death mechanisms, and, as a consequence, the importance of mitochondria in these processes was soon recognized. Early studies showed considerable effort in identifying the mechanisms of Ca(2+) sequestration, precipitation and release by uncouplers of oxidative phosphorylation; however, relatively little information was obtained, and these processes were eventually taken for granted. Here, we re-examine: (a) the thermodynamic aspects of mitochondrial Ca(2+) uptake and release, (b) the insufficiently explained effect of uncouplers in inducing mitochondrial Ca(2+) release, (c) the thermodynamic effects of exogenously added adenine nucleotides on mitochondrial Ca(2+) uptake capacity and precipitate formation, and (d) the elusive nature of the Ca(2+) -phosphate precipitates formed in the mitochondrial matrix.
authors.affiliation: Department of Medical Biochemistry, Semmelweis University, Neurobiochemical Group, Hungarian Academy of Sciences, Budapest, Hungary. chinopoulos.christos@eok.sote.hu
authors.forename: Christos
authors.initials: C
authors.lastname: Chinopoulos
authors.forename: Vera
authors.initials: V
authors.lastname: Adam-Vizi
mesh_terms: D000227:Adenine Nucleotides / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002130:Calcium Phosphates / Q000737:chemistry; D016923:Cell Death; D006801:Humans; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology*; D024101:Mitochondrial Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013816:Thermodynamics; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D000227:Adenine Nucleotides; D002130:Calcium Phosphates; D024101:Mitochondrial Proteins; D014475:Uncoupling Agents; D002118:Calcium