Figure 3.

Less SDH1 is incorporated into the SDH holo-complex, and it accumulates as a soluble protein in sdhaf4. A, SDH1 antibody was used to detect SDH1 abundance in whole mitochondria samples from Ler and sdhaf4 loaded on a BN gel and blotted on a PVDF membrane. Two bands were detected, potentially representing SDH holo-complex and soluble SDH1 protein, as indicated. B, Import of [³⁵S]Met-labeled SDH1 and MPP-α into Ler mitochondria analyzed by SDS-PAGE. Pre, Precursor; Mit, mitochondria; PK, proteinase K; Val, valinomycin (inhibitor for import across the IMM); p, precursor protein; m, mature protein. C, [³⁵S]Met-labeled SDH1 and MPP-α imported into Ler and sdhaf4 mitochondria for 30 and 60 min and separated by BN-PAGE. C I+III, ComplexI+III; C I, Complex I.