Gellerich 2009 PLoS One
|Gellerich FN, Gizatullina Z, Arandarcikaite O, Jerzembek D, Vielhaber S, Seppet E, Striggow F (2009) Extramitochondrial Ca2+ in the nanomolar range regulates glutamate-dependent oxidative phosphorylation on demand. PloS One 4:e8181.|
Abstract: We present unexpected and novel results revealing that glutamate-dependent oxidative phosphorylation (OXPHOS) of brain mitochondria is exclusively and efficiently activated by extramitochondrial Ca2+ in physiological concentration ranges (S0.5= 360 nM Ca2+). This regulation was not affected by RR, an inhibitor of the mitochondrial Ca2+ uniporter. Active respiration is regulated by glutamate supply to mitochondria via aralar, a mitochondrial glutamate/aspartate carrier with regulatory Ca2+-binding sites in the mitochondrial intermembrane space providing full access to cytosolic Ca2+. At micromolar concentrations, Ca2+ can also enter the intramitochondrial matrix and activate specific dehydrogenases. However, the latter mechanism is less efficient than extramitochondrial Ca2+ regulation of respiration/OXPHOS via aralar. These results imply a new mode of glutamate-dependent OXPHOS regulation as a demand-driven regulation of mitochondrial function. This regulation involves the mitochondrial glutamate/aspartate carrier aralar which controls mitochondrial substrate supply according to the level of extramitochondrial Ca2+.
• Keywords: Glutamate/aspartate carrier aralar, Extramitochondrial Ca (2+), Brain mitochondria
Labels: MiParea: Respiration
Tissue;cell: Nervous system
Enzyme: Inner mt-membrane transporter Regulation: Calcium, Inhibitor Coupling state: OXPHOS