Figure 1.

PiC directly interacts with CypD. (A) Recombinant GST and GST-CypD were incubated with mouse heart mitochondrial lysates as described in “Methods” and the resulting complexes were “pulled down” using GSH-beads and immunoblotted for PiC. (B) Recombinant GST-PiC was incubated with increasing amounts of His-tagged CypD (His-CypD) and the resulting complexes were immunoblotted for CypD. In addition, His-CypD was incubated with increasing amounts of GST-PiC and the resulting complexes were purified using Co²⁺-linked beads. (C) Schema illustrating GST-fused mature CypD peptide fragments with sequential deletions on the C-terminus. These fusion proteins were incubated with mouse heart mitochondrial lysates and the resulting complexes were pulled down and detected by western blotting. (D) PiC and CypD models were docked as detailed in “Methods” and the output complexes were grouped into 2 different families where CypD “backface” binds a discrete domain on helix 6 of PiC and CypD CsA-Binding Domain docks the same discrete domain on helix 6 of PiC. CypD residue C203 is shown in sphere projection. (E) CypD and PiC models shown colored by qualitative electrostatic potential. The scales of the potentials are roughly the same for all models (average potential: ± 54 kBT/e). All surfaces were calculated using the protein contact potential function in PyMol.