title: Activity of the mitochondrial calcium uniporter varies greatly between tissues.
abstract: The mitochondrial calcium uniporter is a highly selective channel responsible for mitochondrial Ca(2+) uptake. The mitochondrial calcium uniporter shapes cytosolic Ca(2+) signals, controls mitochondrial ATP production, and is involved in cell death. Here using direct patch-clamp recording from the inner mitochondrial membrane, we compare mitochondrial calcium uniporter activity in mouse heart, skeletal muscle, liver, kidney and brown fat. Surprisingly, heart mitochondria show a dramatically lower mitochondrial calcium uniporter current density than the other tissues studied. Similarly, in Drosophila flight muscle, mitochondrial calcium uniporter activity is barely detectable compared with that in other fly tissues. As mitochondria occupy up to 40% of the cell volume in highly metabolically active heart and flight muscle, low mitochondrial calcium uniporter activity is likely essential to avoid cytosolic Ca(2+) sink due to excessive mitochondrial Ca(2+) uptake. Simultaneously, low mitochondrial calcium uniporter activity may also prevent mitochondrial Ca(2+) overload in such active tissues exposed to frequent cytosolic Ca(2+) activity.
authors.affiliation: Department of Physiology, University of California, San Francisco, San Francisco, California 94158, USA.
authors.forename: Francesca
authors.initials: F
authors.lastname: Fieni
authors.forename: Sung Bae
authors.initials: SB
authors.lastname: Lee
authors.forename: Yuh Nung
authors.initials: YN
authors.lastname: Jan
authors.forename: Yuriy
authors.initials: Y
authors.lastname: Kirichok
mesh_terms: D002001:Adipose Tissue, Brown / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D017136:Ion Transport; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D029721:Drosophila Proteins; C034703:mitochondrial calcium uniporter; D002118:Calcium