Figure 5.

Complementation Studies Using C1qbp^−/− Mouse Fibroblasts

(A) Quantification of C1QBP, COXI, and COXIII levels. Top: WT or C1qbp KO MEFs were transfected with the pcDNA3-C1qbp-IRES-GFP plasmid for 48 hr. Western blotting on total cell extracts was performed with anti-C1QBP, anti-COXI, anti-COXIII, anti-GFP, and anti-VDAC antibodies. VDAC was used as the loading control. Bottom: the mean ratios of band densities in transfected MEFs from blots are shown. Cells transfected with expression constructs for p.Gly244Trp and p.Leu272Pro variants show significantly lower amounts of mature C1QBP and mitochondrial-DNA-encoded proteins (COXI and COXIII). The results represent the mean ± SD of three independent experiments. ^∗∗∗p < 0.005 versus WT transfectant.

(B) Relative mRNA expression of C1qbp alleles normalized to mouse 18S rRNA by quantitative real-time PCR. The results represent the mean ± SD of three independent experiments.

(C and D) Oxygen consumption rate (OCR) profile (C) and histogram of C1qbp KO cells transfected with WT and mutant C1qbp plasmid (D). The histogram shows the basal respiration rate (basal), ATP production rate (ATP), and maximal respiration rate (maximal) calculated from OCR profiles. Data show the mean ± SD of triplicated assays. ^∗∗p < 0.01 and ^∗∗∗p < 0.005 versus WT transfectant.