For cross-link immunoprecipitation, mitochondria enriched heavy membrane fractions (200 μg) from control fibroblasts were chemically cross-linked with 1 mM dithiobis-sulfosuccinimidyl propionate (DSP) (Sigma) in HIM buffer, for 2 h on ice. The reaction was stopped by adding glycine pH 8.0 at 70 mM final concentration for 10 min on ice. Mitochondria were pelleted, rinsed once, and extracted in 200 μl of lysis buffer (10 mM Tris-HCl pH 7.5, 150 mM NaCl, 1% n-dodecyl-D-maltoside (DDM) (Sigma), and complete protease inhibitors (Roche)) on ice for 30 min. The extract was centrifuged at 20,000g at 4°C for 20 min, and the supernatant was precleared overnight with non-coated Dynabeads Protein A (Invitrogen) to reduce non-specific protein binding to the beads. Binding of indicated antibodies to Dynabeads Protein A (Invitrogen) was performed overnight. Antibodies were then cross-linked to the beads using 20 mM dimethyl pimelimidate (DMP) (Sigma). The immunoprecipitation reaction was performed overnight at 4°C. Beads were washed with lysis buffer and samples were eluted using 0.1 M glycine pH 2.5/0.5% DDM, precipitated with trichloroacetic acid and analyzed by mass spectrometry at the IRCM (Institut de Recherches cliniques de Montreal).