Mitochondrial translation products were pulse-labelled in control 143B cells (left panel), COX1∆ (middle panel) and COX2∆ (right panel) cybrids with [35S]-methionine for 30 minutes in the presence of anisomycin to inhibit cytosolic translation. For chase, cells were washed and incubated with fresh culture medium for the indicated time points (T0-T24 hours). Radiolabeled mitochondrial proteins (indicated on the right) were separated by 2D-BN/SDS-PAGE and visualized by autoradiography. A enlarged section of the SCs region at T24 (delimited by a square) shows the co-migration of COX1 with SC I+III2plus (black arrow) in the COX2∆ cybrids relative to the position of canonical SC I+III2 (gray arrow). The identities of MRC complexes and SCs (bottom) are as in Figure 1. Molecular weight markers are indicated on the left. 