Mitochondria pp 97-116 | Cite as

Molecular Structure of the Mitochondrial Citrate Transport Protein

  • Ronald S. Kaplan
  • June A. Mayor
Part of the Advances in Biochemistry in Health and Disease book series (ABHD, volume 2)


The mitochondrial citrate transport protein (i.e., CTP) is located within the inner mitochondrial membrane and in higher eukaryotes catalyzes an obligatory 1:1 exchange of the dibasic form of a tricarboxylic acid (e.g., citrate, isocitrate, or cis-aconitate) for either another tricarboxylate, a dicarboxylate, or phosphoenolpyruvate (Palmieri et al. 1972; Bisaccia et al.1993; Palmieri 2004). The CTP occupies a prominent position within intermediary metabolism since following the efflux of citrate from the mitochondrial matrix and subsequent diffusion across the outer mitochondrial membrane, the resulting cytoplasmic citrate serves as the main carbon source fueling the fatty acid, triacylglycerol, and cholesterol biosynthetic pathways (Watson and Lowenstein 1970; Brunengraber and Lowenstein 1973; Endemann et al. 1982; Conover 1987).


Substrate Binding Site Dime Interface Substrate Protection Bind Site Residue Translocation Pathway 
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  1. Akabas MH, Stauffer DA, Xu M, Karlin A (1992) Acetylcholine receptor channel structure probed in cysteine-substitution mutants. Science 258:307–310CrossRefPubMedGoogle Scholar
  2. Bisaccia F, De Palma A, Dierks T, Kramer R, Palmieri F (1993) Reaction mechanism of the reconstituted tricarboxylate carrier from rat liver mitochondria. Biochim. Biophys. Acta 1142:139–145CrossRefPubMedGoogle Scholar
  3. Brooks BR, Bruccoleri RE, Olafson BD, States DJ, Swaminathan S, Karplus M (1983) CHARMM: a program for macromolecular energy, minimization, and dynamics calculations. J Comp Chem 4:187–217CrossRefGoogle Scholar
  4. Brunengraber H, Lowenstein JM (1973) Effect of (-)-hydroxycitrate on ethanol metabolism. FEBS Lett 36:130–132CrossRefPubMedGoogle Scholar
  5. Chen J-G, Rudnick G (2000) Permeation and gating residues in serotonin transporter. Proc Nat Acad Sci. USA 97: 1044–1049CrossRefPubMedGoogle Scholar
  6. Conover TE (1987) Does citrate transport supply both acetyl groups and NADPH for cytoplasmic fatty acid synthesis? Trends Biochem Sci. 12:88–89CrossRefGoogle Scholar
  7. Endemann G, Goetz PG, Edmond J, Brunengraber H (1982) Lipogenesis from ketone bodies in the isolated perfused rat liver. Evidence for the cytosolic activation of acetoacetate. J Biol Chem 257:3434–3440PubMedGoogle Scholar
  8. Fu D, Sarker RI, Abe K, Bolton E, Maloney PC (2001) Structure/function relationships in OxlT, the oxalate-formate transporter of oxalobacter formigenes. Assignment of transmembrane helix 11 to the translocation pathway. J Biol Chem 276: 8753–8760CrossRefPubMedGoogle Scholar
  9. Gasol E, Jimenez-Vidal M, Chillaron J, Zorzano A, Palacin M (2004) Membrane topology of system xc-light subunit reveals a reentrant loop with substrate-restricted accessibility. J Biol Chem 279:31228–31236CrossRefPubMedGoogle Scholar
  10. Henry LK, Adkins EM, Han Q, Blakely RD (2003) Serotonin and cocaine-sensitive inactivation of human serotonin transporters by methanethiosulfonates targeted to transmembrane domain I. J Biol Chem 278: 37052–37063CrossRefPubMedGoogle Scholar
  11. Holmgren M, Liu Y, Xu Y, Yellen G (1996) On the use of thiol-modifying agents to determine channel topology. Neuropharmacology 35:797–804CrossRefPubMedGoogle Scholar
  12. Kaplan RS (1996) Mitochondrial transport processes. In: Schultz SG, Andreoli T, Brown A, Fambrough D, Hoffman J, Welsh J (eds) Molecular Biology of Membrane Transport Disorders. Plenum Press, New York, pp. 277–302Google Scholar
  13. Kaplan RS (2001) Structure and function of mitochondrial anion transport proteins. J Membrane Biol 179:165–183CrossRefGoogle Scholar
  14. Kaplan RS, Morris HP, Coleman PS (1982) Kinetic characteristics of citrate influx and efflux with mitochondria from Morris hepatomas 3924A and 16. Cancer Res 42:4399–4407PubMedGoogle Scholar
  15. Kaplan RS, Mayor JA, Johnston N, Oliveira DL (1990a) Purification and characterization of the reconstitutively active tricarboxylate transporter from rat liver mitochondria. J Biol Chem 265:13379–13385PubMedGoogle Scholar
  16. Kaplan RS, Oliveira DL, Wilson GL (1990b) Streptozotocin-induced alterations in the levels of functional mitochondrial anion transport proteins. Arch Biochem Biophys 280:181–191CrossRefPubMedGoogle Scholar
  17. Kaplan RS, Mayor JA, Wood DO (1993) The mitochondrial tricarboxylate transport protein. cDNA cloning, primary structure, and comparison with other mitochondrial transport proteins. J Biol Chem 268:13682–13690PubMedGoogle Scholar
  18. Kaplan RS, Mayor JA, Gremse DA, Wood DO (1995). High level expression and characterization of the mitochondrial citrate transport protein from the yeast Saccharomyces cerevisiae. J Biol Chem 270:4108–4114CrossRefPubMedGoogle Scholar
  19. Kaplan RS, Mayor JA, Brauer D, Kotaria R, Walters DE, Dean AM (2000a) The yeast mitochondrial citrate transport protein: probing the secondary structure of transmembrane domain IV and identification of residues that likely comprise a portion of the citrate translocation pathway. J Biol Chem 275:12009–12016CrossRefPubMedGoogle Scholar
  20. Kaplan RS, Mayor JA, Kotaria R, Walters DE, Mchaourab HS (2000b) The yeast mitochondrial citrate transport protein: Determination of secondary structure and solvent accessibility of transmembrane domain IV using site-directed spin labeling. Biochemistry 39:9157–9163CrossRefPubMedGoogle Scholar
  21. Karlin A, Akabas MH (1998) Substituted-cysteine accessibility method. Methods Enzymol 293:123–145CrossRefPubMedGoogle Scholar
  22. Kotaria R, Mayor JA, Walters DE, Kaplan RS (1999) Oligomeric state of wild-type and cysteine-less yeast mitochondrial citrate transport proteins. J Bioenerg Biomemb 31:543–549CrossRefGoogle Scholar
  23. Kramer R, Palmieri F (1992) Metabolite carriers in mitochondria. In: Ernster L (ed) Molecular Mechanisms in Bioenergetics. Elsevier, New York, pp. 359–384CrossRefGoogle Scholar
  24. Leighton BH, Seal RP, Shimamoto K, Amara SG (2002) A hydrophobic domain in glutamate transporters forms an extracellular helix associated with the permeation pathway for substrates. J Biol Chem 277: 29847–29855CrossRefPubMedGoogle Scholar
  25. Ma C, Kotaria R, Mayor JA, Eriks LR, Dean AM, Walters DE, Kaplan RS (2004) The mitochondrial citrate transport protein: probing the secondary structure of transmembrane domain III, identification of residues that likely comprise a portion of the citrate transport pathway, and development of a model for the putative TMDIII-TMDIII’ interface. J Biol Chem 279:1533–1540CrossRefPubMedGoogle Scholar
  26. Ma C, Kotaria R, Mayor JA, Remani S, Walters DE, Kaplan RS (2005) The yeast mitochondrial citrate transport protein: characterization of transmembrane domain III residue involvement in substrate translocation. J Biol Chem 280:2331–2340CrossRefPubMedGoogle Scholar
  27. Ma C, Remani S, Kotaria R, Mayor JA, Walters DE, Kaplan RS (2006) The mitochondrial citrate transport protein: evidence for a steric interaction between glutamine 182 and leucine 120 and its relationship to the substrate translocation pathway and identification of other mechanistically essential residues. Biochim Biophys Acta, Manuscript SubmittedGoogle Scholar
  28. Nury H, Dahout-Gonzalez C, Treqeguet V, Lauguin G, Brandolin G, Pebay-Peyroula E (2005) Structural basis for lipid-mediated interactions between mitochondrial ADP/ATP carrier monomers. FEBS Lett 579:6031–6036CrossRefPubMedGoogle Scholar
  29. Palmieri F (2004) The mitochondrial transporter family (SLC25): physiological and pathological implications. Pflugers Arch - Eur J Physiol 447:689–709CrossRefGoogle Scholar
  30. Palmieri F, Stipani I, Quagliariello E, Klingenberg M (1972) Kinetic study of the tricarboxylate carrier in rat liver mitochondria. Eur J Biochem 26:587–594CrossRefGoogle Scholar
  31. Pebay-Peyroula E, Dahout-Gonzalez C, Kahn R, Trezeguet V, Lauquin GJ-M, Brandolin G (2003) Structure of mitochondrial ADP/ATP carrier in complex with carboxytractyloside. Nature 426:39–44CrossRefPubMedGoogle Scholar
  32. Seal RP, Amara SG (1998) A reentrant loop domain in the glutamate carrier EAAT1 participates in substrate binding and translocation. Neuron 21: 1487–1498CrossRefPubMedGoogle Scholar
  33. Walters DE, Kaplan RS (2004) Homology-modeled structure of the yeast mitochondrial citrate transport protein. Biophys J 87:907–911CrossRefPubMedGoogle Scholar
  34. Watson JA, Lowenstein JM (1970) Citrate and the conversion of carbohydrate into fat. Fatty acid synthesis by a combination of cytoplasm and mitochondria, J Biol Chem 245:5993–6002PubMedGoogle Scholar
  35. West IC (1997) Ligand conduction and the gated-port mechanism of transmembrane transport. Biochim Biophys Acta 1331:213–234PubMedGoogle Scholar
  36. Xu Y, Mayor JA, Gremse D, Wood DO, Kaplan RS (1995) High-Yield bacterial expression, purification, and functional reconstitution of the tricarboxylate transport protein from rat liver mitochondria. Biochem Biophys Res Comm 207:783–789CrossRefPubMedGoogle Scholar
  37. Xu Y, Kakhniashvili DA, Gremse DA, Wood DO, Mayor JA, Walters DE, Kaplan RS (2000) The yeast mitochondrial citrate transport protein: probing the roles of cysteines, Arg181, and Arg189 in transporter function. J Biol Chem 275:7117–7124CrossRefPubMedGoogle Scholar
  38. Ye L, Maloney PC (2002) Structure/function relationships in OxlT, the oxalate/formate antiporter of Oxalobacter formigenes: assignment of transmembrane helix 2 to the translocation pathway. J Biol Chem 277: 20372–20378CrossRefPubMedGoogle Scholar
  39. Zomot E, Kanner BI (2003) The interaction of the gamma-aminobutyric acid transporter GAT-1 with the neurotransmitter is selectively impaired by sulfhydryl modification of a conformationally sensitive cysteine residue engineered into extracellular loop IV. J Biol Chem 278: 42950–42958CrossRefPubMedGoogle Scholar

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© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Ronald S. Kaplan
  • June A. Mayor

There are no affiliations available

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