Figure 4.

Western blot analysis of mitochondrial proteins. (A, C) Twenty micrograms of total cellular proteins from various cell lines were electrophoresed through a denaturing polyacrylamide gel, electroblotted, and hybridized with antibodies for 10 subunits of OXPHOS (three encoded by mtDNA and seven encoded by nuclear genes), with VDAC as a loading control. (B, D) Quantification of levels of mitochondrial proteins: three mtDNA-encoding subunits (B) and seven nucleus-encoding subunits (D). The average content of each subunit was normalized to the average content of VDAC in the mutant and wild-type cell lines. The calculations were based on three independent determinations. The error bars indicate 2 SDs of the means. P indicates the significance (t-test) of the differences among the various cell lines.