1. The protein contains a special signal in the leader amino acids, shown here in red, that is recognized by a class of cytoplasmic chaperone called MSF (mitochondiral-import stimulating factor), in emerald green.

2. The association of the MSF with the growing protein prevents it from folding into its active conformation.

3. When the protein is complete, it is directed to the mitochondrion outer membrane by MSF.

4. In the outer mitochondrial membrane are two proteins that serve as a receptor for MSF, shown here in green and purple. When MSF contacts this receptor, it binds, anchoring the matrix protein to the membrane.

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