FIGURE 5.

Effect of transient suppression of expression of NDUFB3 and NDUFAF5 on the assembly of complex I. Samples were prepared at 192 h from human 143B cells that had been transfected three times at 72-h intervals with (a), negative control siRNA or (b and c), siRNA specific for NDUFB3 and NDUFAF5, respectively. Inner mitochondrial membrane proteins were fractionated by BN-PAGE, Western-blotted and probed with antibodies against the peripheral arm subunit NDUFS2 and assembly factor NDUFAF3. Antibodies against complex III (UQCRC1) and complex IV (COX5B) were used as loading controls on NDUFS2 and NDUFAF3 blots, respectively. CI, complex I; CIII₂, complex III dimer; CIV, complex IV; CIII₂+CIV, assembly of complex III dimer and complex IV; CI-200 kDa, complex I sub-complex.