(I) Mitochondria from the indicated yeast strains (pex19Δ, pex19Δmsp1Δ, and pex13Δmsp1Δpex19Δ) expressing Pot1-V5 (under its endogenous promotor) were either left untreated (nt) (lane 1,4,7) or were treated with proteinase K in high fidelity buffer (PK-HF) (cutting control, lane 2,5,8) or low fidelity buffer (PK-LF) (protease protection assay, lane 3,6,9) and separated by SDS-PAGE and immunoblotted for Mia40 (intermembrane space) (α-Mia40), Pot1-V5 (α-V5), porin (outer membrane) (α-porin) and Tom22 (outer membrane but partially proteinase exposed) (α-Tom22). 