Biochemical characterization of a new mitochondrial transporter of dephosphocoenzyme A in Drosophila melanogaster

• Published in: Biochimica et biophysica acta. Bioenergetics 2017-02, Vol.1858 (2), p.137-146
• Main Authors: Vozza, Angelo, De Leonardis, Francesco, Paradies, Eleonora, De Grassi, Anna, Pierri, Ciro Leonardo, Parisi, Giovanni, Marobbio, Carlo Marya Thomas, Lasorsa, Francesco Massimo, Muto, Luigina, Capobianco, Loredana, Dolce, Vincenza, Raho, Susanna, Fiermonte, Giuseppe
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Bioenergetics; Biological Transport - physiology; Carrier Proteins - metabolism; Coenzyme A; Coenzyme A - metabolism; Cytosol - metabolism; Dephosphocoenzyme A; Drosophila melanogaster - metabolism; Escherichia coli - metabolism; Kinetics; Mitochondria - metabolism; Mitochondrial carrier; Mitochondrial Membrane Transport Proteins - metabolism; Neurodegenerative disease; Protein Biosynthesis - physiology; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - metabolism; Sequence Alignment; Transport
• ISSN: 0005-2728; 1879-2650
• DOI: 10.1016/j.bbabio.2016.11.006

CoA is an essential cofactor that holds a central role in cell metabolism. Although its biosynthetic pathway is conserved across the three domains of life, the subcellular localization of the eukaryotic biosynthetic enzymes and the mechanism behind the cytosolic and mitochondrial CoA pools compartmentalization are still under debate. In humans, the transport of CoA across the inner mitochondrial membrane has been ascribed to two related genes, SLC25A16 and SLC25A42 whereas in D. melanogaster genome only one gene is present, CG4241, phylogenetically closer to SLC25A42. CG4241 encodes two alternatively spliced isoforms, dPCoAC-A and dPCoAC-B. Both isoforms were expressed in Escherichia coli, but only dPCoAC-A was successfully reconstituted into liposomes, where transported dPCoA and, to a lesser extent, ADP and dADP but not CoA, which was a powerful competitive inhibitor. The expression of both isoforms in a Saccharomyces cerevisiae strain lacking the endogenous putative mitochondrial CoA carrier restored the growth on respiratory carbon sources and the mitochondrial levels of CoA. The results reported here and the proposed subcellular localization of some of the enzymes of the fruit fly CoA biosynthetic pathway, suggest that dPCoA may be synthesized and phosphorylated to CoA in the matrix, but it can also be transported by dPCoAC to the cytosol, where it may be phosphorylated to CoA by the monofunctional dPCoA kinase. Thus, dPCoAC may connect the cytosolic and mitochondrial reactions of the CoA biosynthetic pathway without allowing the two CoA pools to get in contact. •The fruit fly mitochondrial dephosphocoenzyme A carrier (dPCoAC) has been identified.•dPCoAC exchanges mitochondrial dephosphocoenzyme A (dPCoA) for cytosolic ADP.•dPCoAC is inhibited by coenzyme A (CoA).•CoA synthesis from dPCoA occurs both in the mitochondrial matrix and in the cytosol.•Mitochondrial and cytosolic parts of CoA biosynthetic route are connected by dPCoAC.