Novel intersection of mitochondrial fatty acid synthesis and iron-sulfur biogenesis

The mitochondrial acyl-carrier protein (ACP) functions in the synthesis of fatty acids within the mitochondrial matrix. Fatty acids are elongated on the covalently bound 4’-phosphopantetheine cofactor on ACP. ACP has a second essential function within the mitochondria in the biogenesis of iron-sulfur clusters. Cells depleted of ACP are impaired in FeS cluster formation throughout the cell. ACP is a stable subunit of the cysteine desulfurase (Nfs1) and Isd11 subcomplex that generates sulfide ions for FeS cluster formation. The FeS defect observed in cells depleted of ACP can be partially suppressed by overexpression of the mitochondrial iron transporter Mrs3. The stability of ACP is dependent of the iron status of mitochondria. Thus, the central role of Acp1 in mitochondrial fatty acid synthesis, lipoic acid formation and FeS cluster biogenesis suggests that these processes are tied to Fe availability within the mitochondria