Figure 7.

Model for StAR’s entry into the mitochondria. The amphipathic helical mitochondrial leader peptide transverses the outer mitochondrial membrane (OMM) and inner mitochondrial membrane (IMM) by using standard mitochondrial protein-import machinery. The protease-resistant domain comprising residues 63–188 slows protein unfolding and mitochondrial entry, permitting the biologically active protease-accessible carboxyl-terminal domain (residues 189–285) to have more opportunity to interact with the OMM.