FIGURE 5:

Mfn1 is required for Gp78-dependent mitophagy upon mitochondrial depolarization. (A) Western blots show knockdown of endogenous Mfn1 and Mfn2 expression in HEK293 cells transfected with siControl or siMfn1 (left) or siMfn2 (right) for 24 and 48 h. Endogenous Mfn1/Mfn2 expression was quantified by densitometry relative to β-actin (n = 3, ±SEM; *p < 0.05, **p < 0.01). (B) siMfn1- or siMfn2-treated HEK293 cells were transfected with empty vector or Flag-gp78. Cells were either untreated (CTL) or treated with CCCP for 24 h and labeled with antibodies to Flag and mitochondrial OxPhosV. Bar graphs show the percentage loss of mitochondrial mass of CCCP-treated cells relative to untreated cells ((mitochondrial area[CTL − CCCP]/mitochondrial area[CTL]) × 100; see Supplemental Table S1 for mitochondrial area values).