MtFt overexpression reduces both cytosolic and mitochondrial aconitase activities. Clone B9 cells (30% confluence), grown for 72 hours without or with tetracycline, were harvested and homogenized in lysis buffer (sucrose 0.25 M, 10 mM HEPES, pH 7.4, 0.15% bovine serum albumin). Cytosolic (A) and mitochondrial (B) fractions separated by differential centrifugation and assayed for aconitase activity. t test ^*P < .01 compared with tet-on cells; ^**P < .05 compared with tet-on cells. Data shown are the means ± SD of triplicate determinations from a typical experiment that was performed 3 times.