Figure 3. The PD-a module of complex I is a structural component of the respirasome subcomplex
(A–I) Blue-native PAGE and immunoblotting analysis of the RS in control (Ctrl) and TIMMDC1−/− (KO) cells with sequence-specific KD of nuclear-encoded, constitutive subunits of CI. Eight subunits of N (A), nine subunits of Q (C), four subunits of PP-a (E), and five subunits of PP-b (G) were knocked down in a total of 26 TIMMDC1−/− cell lines. Digitonin-solubilized protein was separated by 3%–11% blue-native PAGE, and the RS was immunoblotted with anti-NDUFB6 antibody (A, C, E, and G). Quantitative analysis of RS levels was performed with KD of N (B), Q (D), PP-a (F), and PP-b (I) modules. PP-b+PD-a-containing complex in TIMMDC1−/− cells with KD of PP-b module (G) was quantified as in (H).
(J and K) Blue-native PAGE and immunoblotting analysis of the RS in control (Ctrl) and TIMMDC1−/− (KO) cells with sequence-specific KD of nuclear encoded constitutive subunits of PD-a modules. Six subunits of the PD-a modules were knocked down independently in six TIMMDC1−/− cells. Digitonin-solubilized protein was separated by 3%–11% blue-native PAGE, and the RS was immunoblotted with anti-NDUFB6 antibody (J). Quantitative analysis of RS levels was performed with KD of PD-a (K).
(L and M) Blue-native PAGE and immunoblotting analysis of the RS in control (Ctrl) and TIMMDC1−/− (KO) cells with sequence-specific KD of assembly factors. ATP5SL, FOXRED1, and TMEM70 were knocked down independently in three TIMMDC1−/− cells. Digitonin-solubilized protein was separated by 3%–11% blue-native PAGE, and the RS was immunoblotted with anti-NDUFB6 antibody (L). Quantitative analysis of the RS levels was performed with the KD of ATP5SL, FOXRED1, and TMEM70 (M).
(N and O) Blue-native PAGE and immunoblotting analysis of the RS in control (Ctrl) and TIMMDC1−/− (KO) cells with sequence-specific KD of nuclear-encoded constitutive subunits of PD-b modules. Six subunits of the PD-b modules were knocked down independently in TIMMDC1−/− cells. Digitonin-solubilized protein was separated by 3%–11% blue-native PAGE, and the RS was immunoblotted with anti-NDUFB6 antibody (N). Quantitative analysis of RS levels was performed with KD of PD-b (O).
TOM70 was used as an internal control. Quantitative data were generated from three independent experiments. Data are presented as the means ± SEM. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001.