The acuH gene of Aspergillus nidulans, required for growth on acetate and long-chain fatty acids, encodes a putative homologue of the mammalian carnitine/acylcarnitine carrier.
The Aspergillus nidulans acuH gene, required for growth on acetate and long-chain fatty acids, was cloned by complementation of the acuH13 mutation. Northern blotting analysis showed that transcription of the acuH gene occurs in acetate-grown mycelium and at higher levels in oleate-grown mycelium, but not during growth on glucose minimal medium. The acuH gene encodes a protein of 326 amino acids that belongs to the mitochondrial carrier family. The ACUH protein contains three related segments of approximately 100 amino acids in length, each segment comprising two hydrophobic domains that are probably folded into two transmembrane alpha-helices linked by an extensive polar region. Sequence comparisons suggest that the acuH gene of A. nidulans encodes the homologue of the carnitine/acylcarnitine carrier of rat and man. The uncharacterised proteins YOR100C of Saccharomyces cerevisiae, COLT of Drosophila melanogaster, and DIF-1 of Caenorhabditis elegans also seem to be homologues of ACUH. In addition to the motifs present in all members of the mitochondrial carrier family, we propose the highly conserved motif R(A,S)(V,F)PANAA(T,C)F within the sixth hydrophobic domain of these proteins as the characteristic feature of the carnitine carrier subfamily. The proposed function of the ACUH protein is the transport of acetylcarnitine molecules from the cytosol to the mitochondrial matrix, a process required during growth on acetate or on long-chain fatty acids.
De Lucas
J R
JR
Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Alcalá, Ctra. Madrid-Barcelona Km 33, E-28871 Alcalá de Henares (Madrid), Spain.
Domínguez
A I
AI
Valenciano
S
S
Turner
G
G
Laborda
F
F
D000085:Acetates / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001233:Aspergillus nidulans / Q000235:genetics* / Q000254:growth & development; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002331:Carnitine / Q000378:metabolism*; D002333:Carnitine Acyltransferases; D002352:Carrier Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D003470:Culture Media / Q000737:chemistry; D005227:Fatty Acids / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics*; D005800:Genes, Fungal; D006801:Humans; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D051381:Rats; D016415:Sequence Alignment
D000085:Acetates; D002352:Carrier Proteins; D003470:Culture Media; D005227:Fatty Acids; D005656:Fungal Proteins; D026901:Membrane Transport Proteins; C120109:SLC25A20 protein, human; D002333:Carnitine Acyltransferases; D002331:Carnitine