A novel ADP/ATP transporter in the mitosome of the microaerophilic human parasite Entamoeba histolytica.
Recent data suggest that microaerophilic and parasitic protozoa, which lack oxidative phosphorylation, nevertheless contain mitochondrial homologs [1-6], organelles that share common ancestry with mitochondria. Such widespread retention suggests there may be a common function for mitochondrial homologs that makes them essential for eukaryotic cells. We determined the mitochondrial carrier family (MCF) complement of the Entamoeba histolytica mitochondrial homolog, also known as a crypton [5] or more commonly as a mitosome [3]. MCF proteins support mitochondrial metabolic energy generation, DNA replication, and amino-acid metabolism by linking biochemical pathways in the mitochondrial matrix with those in the cytosol [7]. MCF diversity thus closely mirrors important facets of mitochondrial metabolic diversity. The Entamoeba histolytica mitosome has lost all but a single type of MCF protein, which transports ATP and ADP via a novel mechanism that is not reliant on a membrane potential. Phylogenetic analyses confirm that the Entamoeba ADP/ATP carrier is distinct from archetypal mitochondrial ADP/ATP carriers, an observation that is supported by its different substrate and inhibitor specificity. Because many functions of yeast and human mitochondria rely on solutes transported by specialized members of this family, the Entamoeba mitosome must contain only a small subset of these processes requiring adenine nucleotide exchange.
Chan
Ka Wai
KW
Dunn Human Nutrition Unit, Medical Research Council, Cambridge, UK.
Slotboom
Dirk-Jan
DJ
Cox
Sian
S
Embley
T Martin
TM
Fabre
Olivier
O
van der Giezen
Mark
M
Harding
Marilyn
M
Horner
David S
DS
Kunji
Edmund R S
ER
León-Avila
Gloria
G
Tovar
Jorge
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001499:Bayes Theorem; D015153:Blotting, Western; D002458:Cell Fractionation; D019295:Computational Biology; D018076:DNA, Complementary / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004748:Entamoeba histolytica / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D013294:Lactococcus lactis; D000226:Mitochondrial ADP, ATP Translocases / Q000235:genetics* / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D015388:Organelles / Q000378:metabolism*; D010802:Phylogeny; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae; D017422:Sequence Analysis, DNA; D022161:Transport Vesicles / Q000378:metabolism
D018076:DNA, Complementary; D000226:Mitochondrial ADP, ATP Translocases