PROSITE documentation PDOC00189
Solute carrier (Solcar) repeat profile


Different types of substrate carrier proteins involved in energy transfer are found in the inner mitochondrial membrane [1,2,3,4,5]. These are:

  • The ADP,ATP carrier protein (AAC) (ADP/ATP translocase) which exports ATP into the cytosol and imports ADP into the mitochondrial matrix. The sequence of AAC has been obtained from various mammalian, plant and fungal species.
  • The 2-oxoglutarate/malate carrier protein (OGCP), which exports 2-oxoglutarate into the cytosol and imports malate or other dicarboxylic acids into the mitochondrial matrix. This protein plays an important role in several metabolic processes such as the malate/aspartate and the oxoglutarate/isocitrate shuttles.
  • The phosphate carrier protein, which transports phosphate groups from the cytosol into the mitochondrial matrix.
  • The brown fat uncoupling protein (UCP) which dissipates oxidative energy into heat by transporting protons from the cytosol into the mitochondrial matrix.
  • The tricarboxylate transport protein (or citrate transport protein) which is involved in citrate-H+/malate exchange. It is important for the bioenergetics of hepatic cells as it provides a carbon source for fatty acid and sterol biosyntheses, and NAD for the glycolytic pathway.
  • The Grave's disease carrier protein (GDC), a protein of unknown function recognized by IgG in patients with active Grave's disease.
  • Yeast mitochondrial proteins MRS3 and MRS4. The exact function of these proteins is not known. They suppress a mitochondrial splice defect in the first intron of the COB gene and may act as carriers, exerting their suppressor activity by modulating solute concentrations in the mitochondrion.
  • Yeast mitochondrial FAD carrier protein (gene FLX1).
  • Yeast protein ACR1 [6], which seems essential for acetyl-CoA synthase activity.
  • Yeast protein PET8.
  • Yeast protein PMT.
  • Yeast protein RIM2.
  • Yeast protein YHM1/SHM1.
  • Yeast protein YMC1.
  • Yeast protein YMC2.
  • Yeast hypothetical proteins YBR291c, YEL006w, YER053c, YFR045w, YHR002w, and YIL006w.
  • Caenorhabditis elegans hypothetical protein K11H3.3.

Two other proteins have been found to belong to this family, yet are not localized in the mitochondrial inner membrane:

  • Maize amyloplast Brittle-1 protein. This protein, found in the endosperm of kernels, could play a role in amyloplast membrane transport.
  • Candida boidinii peroxisomal membrane protein PMP47 [7]. PMP47 is an integral membrane protein of the peroxisome and it may play a role as a transporter.

These proteins all seem to be evolutionary related. Structurally, they consist of three tandem repeats of a domain of approximately one hundred residues. Each of these domains contains two transmembrane regions.

The profile we developed covers the entire solute carrier (Solcar) repeat.

Last update:

August 2003 / Pattern removed and profile added.


Technical section

PROSITE method (with tools and information) covered by this documentation:

SOLCAR, PS50920; Solute carrier (Solcar) repeat profile  (MATRIX)


1AuthorsKlingenberg M.
TitleMechanism and evolution of the uncoupling protein of brown adipose tissue.
SourceTrends Biochem. Sci. 15:108-112(1990).
PubMed ID2158156

2AuthorsWalker J.E.
SourceCurr. Opin. Struct. Biol. 2:519-526(1992).

3AuthorsKuan J. Saier M.H. Jr.
SourceCRC Crit. Rev. Biochem. 28:209-233(1993).

4AuthorsKuan J. Saier M.H. Jr.
TitleExpansion of the mitochondrial carrier family.
SourceRes. Microbiol. 144:671-672(1993).
PubMed ID8140286

5AuthorsNelson D.R. Lawson J.E. Klingenberg M. Douglas M.G.
TitleSite-directed mutagenesis of the yeast mitochondrial ADP/ATP translocator. Six arginines and one lysine are essential.
SourceJ. Mol. Biol. 230:1159-1170(1993).
PubMed ID8487299

6AuthorsPalmieri F.
TitleMitochondrial carrier proteins.
SourceFEBS Lett. 346:48-54(1994).
PubMed ID8206158

7AuthorsJank B. Habermann B. Schweyen R.J. Link T.A.
TitlePMP47, a peroxisomal homologue of mitochondrial solute carrier proteins.
SourceTrends Biochem. Sci. 18:427-428(1993).
PubMed ID8291088

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