Detection of a 35 kDa PGC-1α isoform by different antibodies, and down-regulation of the protein by PGC-1α siRNAs. A) Total protein extracts of SH-SY5Y cells were analyzed by Western blotting with anti-PGC-1α antibodies. B) Purified mitochondria and the remaining cytosolic fraction including nucleus were analyzed by Western blotting with P-120, anti-HSP60, anti-Histone H3, and anti-GAPDH antibodies. C) HEK cells were transiently transfected with scrambled siRNA (lane 1) or two separate siRNAs against PGC-1α (lanes 2 and 3), followed by Western blot analysis with P-120 and actin antibodies.