Transport of 35 kDa PGC-1α depends on the VDAC protein and the mitochondrial membrane potential. A) Immunoelectron microscopy showing colocalization of mitochondrial PGC-1α and VDAC. White and black arrows indicate VDAC (10 nm) and PGC-1α (5 nm) immunoGold labeling in mouse hippocampus tissue. B) Immunoblot analysis of the second-dimension SDS-PAGE gels followed by BN-PAGE analysis of native mitochondrial protein complexes with P-120, anti-Histone H3, and anti-GAPDH antibodies. C) HEK cells were transfected with scrambled control siRNA (lane 1), two separate VDAC siRNAs (lanes 2 and 3), or treated with valinomycin. Mitochondrial lysates were analyzed by Western blotting with P-120, anti-VDAC, and anti-Tom40 antibodies.