Figure 2.

Mitochondrial ATP production but not glycolysis is sufficient to support nuclear transport. (A) Nuclear import of H1 inhibited by an uncoupler of mitochondrial oxidative phosphorylation (Top, 1 μM FCCP) or by a mixture of mitochondrial respiratory chain and F₀F₁-ATPase inhibitors (Bottom, 1 μg/ml each of rotenone, antimycin, oligomycin; Rot/Anti/Oligo), but not by inhibitors of glycolysis (Middle, 6 mM 2-deoxyglucose plus 0.5 mM iodacetate, DOG/IA). Exposure time to inhibitors was 30 min. Horizontal bars = 10 μm; vertical bars = fluorescence scale of 0–255 arbitrary units as in Fig. 1. (B) Average nuclear/cytoplasmic fluorescence ratio for fluorescein-isothiocyanate-labeled H1 injected into the cytosol of controls and cells treated with FCCP/DOG, FCCP, DOG/IA, and Rot/Anti/Oligo. (C) Cellular ATP levels and ATP/ADP ratios in cardiomyocytes after treatments with mitochondrial or glycolytic inhibitors.