Cellular expression and alternative splicing of SLC25A23, a member of the mitochondrial Ca2+-dependent solute carrier gene family.
The transport of metabolites across the inner mitochondrial membrane is mediated by a large superfamily of mitochondrial solute carrier (MSC) proteins. A novel human member of the MSC gene family named SLC25A23, with homologs in mammalian and non-mammalian species has been recently identified together with two close paralogs, SLC25A24 and SLC25A25. These genes encode the human isoforms of the ATP-Mg/Pi carrier described in whole mitochondria. We report here the cellular expression and alternative splicing of SLC25A23. The gene encodes a 468 amino acids polypeptide, named SCaMC-3, with a bipartite structure typical of calcium-binding mitochondrial solute carrier (CaMSC) proteins. The amino-terminal portion harbors three canonical EF-hand calcium-binding domains while the carboxyl-terminal portion of SCaMC-3 has the characteristic features of the MSC superfamily. Northern blot analysis reveals the presence of the transcript in brain, heart, skeletal muscle, liver and small intestine. The SLC25A23 gene undergoes alternative splicing suggesting a modular nature of the encoded product. Three out of four putative protein isoforms lack a significant portion of the third mitochondrial carrier signature. The most common SCaMC-3 isoform shows a mitochondrial subcellular localization when transfected in HeLa cells and is able to bind calcium by Ca(2+)-dependent mobility shift assays. We believe that our study will contribute to a better knowledge of this family of mitochondrial carriers.
Bassi
Maria Teresa
MT
Istituto Scientifico Eugenio Medea "La Nostra Famiglia", Via Don Luigi Monza, 20 22040 Bosisio Parini (LC), Italy.
Manzoni
Marta
M
Bresciani
Roberto
R
Pizzo
Maria Teresa
MT
Della Monica
Antonella
A
Barlati
Sergio
S
Monti
Eugenio
E
Borsani
Giuseppe
G
D017398:Alternative Splicing; D017920:Antiporters / Q000737:chemistry / Q000235:genetics*; D002135:Calcium-Binding Proteins; D003001:Cloning, Molecular; D006367:HeLa Cells; D006801:Humans; D024101:Mitochondrial Proteins / Q000235:genetics; D014018:Tissue Distribution; D014162:Transfection
C086357:ATP-Mg-Pi carrier proteins, mitochondria; D017920:Antiporters; D002135:Calcium-Binding Proteins; D024101:Mitochondrial Proteins; C487500:SLC25A24 protein, human