SLC25A34

Model summary

A multi-pass transporter embedded in the mitochondrial inner membrane that uses a tripartite carrier architecture to exchange small metabolites, prominently amino acids and related organic acids. By alternating access across the membrane, it sustains mitochondrial amino acid pools and indirectly supports pathways that intersect with photorespiration. Its transient protein-binding capacity likely stabilizes assembly and regulation within inner-membrane metabolite networks.

Predicted Gene Ontology terms

1. 01

   I begin with the InterPro architecture.

   The sequence is covered almost end-to-end by IPR023395 (Mitochondrial carrier protein domain superfamily, residues 3–303), establishing membership in the mitochondrial carrier fold. Within this scaffold, IPR051508 (Mitochondrial Carrier Antiporter family, residues 2–298) specifies the canonical solute carrier 25 (MCF) antiport mechanism. The membrane-embedded core is built from three tandem repeats of transmembrane modules: IPR018108 (Mitochondrial carrier protein, transmembrane region repeat) occurs three times—[4–97], [101–198], and [204–296]—together forming the characteristic six-helix, tripartite architecture of mitochondrial carriers. This ordered arrangement causes alternating-access transport across the inner membrane and supports obligate antiport of small metabolites.

2. 02

   This carrier architecture dictates molecular function.

   The three-repeat, six-helix fold with conserved gating motifs enforces substrate exchange rather than uniport, aligning with an antiporter mechanism. Such carriers frequently require transient protein contacts for biogenesis and regulation, consistent with GO:0005515 protein binding as a basal molecular function that stabilizes assembly and interaction with partner complexes.

3. 03

   From function to process, the antiporter fold and substrate preference point to amino acid and related metabolite exchange.

   The explicit biological processes converge on this: GO:0003333 amino acid transmembrane transport follows directly from the carrier’s substrate class; GO:0009853 photorespiration is explained by mitochondrial handling of glycine, serine, and one-carbon intermediates that feed into the photorespiratory pathway; and GO:1903825 organic acid transmembrane transport reflects the broader solute repertoire typical of MCF carriers that shuttle organic acids and amino acids. Together, these processes situate the transporter at a metabolic junction that balances mitochondrial and cytosolic nitrogen and carbon flux.

4. 04

   Cellular location is dictated by the fold itself.

   The three tandem transmembrane repeats and antiporter family membership necessitate insertion into the mitochondrial inner membrane, matching GO:0005743 mitochondrial inner membrane and the experimentally supported matrix-facing carrier topology. This inner-membrane residency positions the transporter to couple cytosolic exchange with matrix-localized pathways.

5. 05

   Mechanistically, the protein operates as an inner-membrane antiporter that exchanges amino acids and related solutes.

   Its three-repeat architecture alternates between matrix-open and cytosol-open states, enabling exchange that sustains mitochondrial amino acid pools and indirectly supports organic acid balance. I hypothesize that it transiently binds assembly and regulatory partners (consistent with protein binding) such as other mitochondrial carriers and matrix enzymes that channel photorespiratory and amino-acid pathways. Likely partners include inner-membrane biogenesis factors and neighboring carriers that coordinate substrate flow, ensuring efficient exchange between the matrix and cytosol.