Fig 3. ND5 mutant mitochondria have reduced levels of stored calcium.
Free cytoplasmic calcium [Ca2+]c was measured using the ratiometric dye fura-2 AM on an epifluorescence imaging system. Thapsigargin was used to block the Ca2+-ATPase to release endoplasmic reticulum (ER) calcium stores, followed by the addition of ionomycin to release mitochondrial calcium. Calcium release from ER stores was not different between control (CON) cybrids and ND5 mutant cybrids, but was significantly reduced in ρ0 cells. However, calcium release from mitochondrial stores was significantly lower in ND5 mutant cybrids lower (66.4 ± 15.8%) that CON cybrids. Stored mitochondrial calcium was also significantly lower in ρ0 cells compared to CON cybrids (21.3 ± 11.7%). Data is mean ± s.d. n = 3.*p<0.05.