The Aspergillus nidulans acuL gene encodes a mitochondrial carrier required for the utilization of carbon sources that are metabolized via the TCA cycle.
In Aspergillus nidulans, the utilization of acetate as sole carbon source requires several genes (acu). Most of them are also required for the utilization of fatty acids. This is the case for acuD and acuE, which encode the two glyoxylate cycle-specific enzymes, isocitrate lyase and malate synthase, respectively, but also for acuL that we have identified as AN7287, and characterized in this study. Deletion of acuL resulted in the same phenotype as the original acuL217 mutant. acuL encodes a 322-amino acid protein which displays all the structural features of a mitochondrial membrane carrier, and shares 60% identity with the Saccharomyces cerevisiae succinate/fumarate mitochondrial antiporter Sfc1p (also named Acr1p). Consistently, the AcuL protein was shown to localize in mitochondria, and partial cross-complementation was observed between the S. cerevisiae and A. nidulans homologues. Extensive phenotypic characterization suggested that the acuL gene is involved in the utilization of carbon sources that are catabolized via the TCA cycle, and therefore require gluconeogenesis. In addition, acuL proves to be co-regulated with acuD and acuE. Overall, our data suggest that AcuL could link the glyoxylate cycle to gluconeogenesis by exchanging cytoplasmic succinate for mitochondrial fumarate.
Laboratoire VEAC, Université Paris-Sud 11, Faculté des Sciences, Bât. 360, Rue du Doyen André Guinier, 91405 Orsay, France. Electronic address: drir.michelflipphi@gmail.com.
Michel
M
Flipphi
Laboratoire VEAC, Université Paris-Sud 11, Faculté des Sciences, Bât. 360, Rue du Doyen André Guinier, 91405 Orsay, France; Pôle Risques MRSH-CNRS, EA2608, Université de Caen, Esplanade de la Paix, 14032 Caen, France. Electronic address: nathalie.oestreicher@u-psud.fr.
Nathalie
N
Oestreicher
IFR141-IPSIT, Plateforme d'Imagerie Cellulaire, Université Paris-Sud 11, Faculté de Pharmacie, Tour E1, 5 Rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France. Electronic address: valerie.nicolas@u-psud.fr.
Valérie
V
Nicolas
Service de Biologie Cellulaire, Université Paris-Sud 11, Faculté des Sciences, Bât. 336, Rue du Doyen André Guinier, 91405 Orsay, France. Electronic address: audrey.guitton@u-psud.fr.
Audrey
A
Guitton
Laboratoire VEAC, Université Paris-Sud 11, Faculté des Sciences, Bât. 360, Rue du Doyen André Guinier, 91405 Orsay, France; Pôle Risques MRSH-CNRS, EA2608, Université de Caen, Esplanade de la Paix, 14032 Caen, France. Electronic address: christian.velot@u-psud.fr.
Christian
C
Vélot
D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002244:Carbon / Q000378:metabolism*; D002952:Citric Acid Cycle; D005650:Fumarates / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D005800:Genes, Fungal; D005943:Gluconeogenesis; D008928:Mitochondria / Q000378:metabolism / Q000648:ultrastructure; D024101:Mitochondrial Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000235:genetics; D019802:Succinic Acid / Q000378:metabolism
D005650:Fumarates; D005656:Fungal Proteins; D024101:Mitochondrial Proteins; D002244:Carbon; D019802:Succinic Acid
Aspergillus nidulans; Cross-complementation; Gluconeogenesis; Glyoxylate pathway; Succinate–fumarate antiport; TCA cycle