Figure 1.

Human ANT1 expression in C2C12 myotubes. (A) WT ANT1 was expressed in C2C12 myotubes (DM4) for 24 h prior to fixation and immunocytochemistry. Cells were immunostained for the HA epitope tag of recombinant ANT1 (in green) and for the COX1 subunit of the mitochondrial respiratory chain (in red). The merged image shows co-localization of these two mitochondrial IM proteins (in yellow). (B) A high-magnification merged image (colors are as in A) of a multinucleated myotube expressing WT ANT1. (C) Expression of WT ANT1 in DM4 myotubes did not cause apoptosis, as determined by negative staining with the apoptotic markers, Annexin V (in green) and propidium iodide (in red). DM4 myotubes treated with 1 μM staurosporine for 24 h caused apoptosis as shown by annexin V and propidium iodide positive staining. (D) Cell viability assessed by MTT assay in DM4 myotubes expressing exogenous WT, or mutant ANT1 (A114P or V289M), or GFP control, for 48 h, and treated with (+STS, 24 h) or without (−STS) 1 μM staurosporine (n = 4 independent experiments).