2.A.47 The Divalent Anion:Na⁺ Symporter (DASS) Family Functionally characterized proteins of the DASS family (also called the SLC13 family) transport (1) organic di- and tricarboxylates of the Krebs Cycle as well as dicarboxylate amino acid, (2) inorganic sulfate and (3) phosphate. These proteins are found in Gram-negative bacteria, cyanobacteria, archaea, plant chloroplasts, yeast and animals. They vary in size from 432 amino acyl residues (M. jannaschii) to 923 residues (Saccharomyces cerevisiae). The three S. cerevisiae proteins are large (881-923 residues); the animal proteins are substantially smaller (539-616 residues), and the bacterial proteins are still smaller (461-612 residues). They exhibit 11-14 putative transmembrane α-helical spanners (TMSs). An 11 TMS model for the animal NaDC-1 and hNaSi-1 carriers has been proposed (Li and Pajor, 2003; Pajor, 1999). Two serine residues in the human sulfate transporter, hNaSi-1 (Q9BZW2), one in TMS 5 and one in TMS 6, are required for sulfate transport (Li and Pajor, 2003). The former carrier and the other NaDC isoforms cotransport 3 Na⁺ with each dicarboxylate. Protonated tricarboxylates are also cotransported with 3 Na⁺. Several organisms possess multiple paralogues of the DASS family (e.g., 4 for E. coli; 2 for H. influenzae, 3 for S. cerevisiae, and at least 4 for C. elegans). The phylogenetic tree for the DASS family reveals six clusters as follows: (1) all animal homologues; (2) all yeast proteins; (3) a functionally uncharacterized protein from Ralstonia eutrophus; (4) three E. coli proteins plus one from H. influenzae and one from spinach chloroplasts (the SodiT1 oxoglutarate:malate translocator); (5) an E. coli Orf that clusters loosely with a sulfur deprivation regulated protein of Synechocystis, and (6) an M. jannaschii protein that clusters loosely with an H. influenzae Orf. Distant homologues of DASS family proteins may include members of the Ars (arsenite exporter) (TC #3.A.4) family as well as the NhaB (TC #2.A.34) and NhaC (TC #2.A.35) Na⁺/H⁺ antiporter families. The DASS family is therefore a member of the ion transporter (IT) superfamily (Rabus et al., 1999). The generalized transport reaction catalyzed by the DASS family proteins is probably: Anion^2- (out) + nM⁺ [Na⁺ or H⁺] (out) → Anion^2- (in) + nM⁺ (in).
This family belongs to the IT Superfamily.
References:
Bun-Ya, M., K. Shikata, S. Nakade, C. Yompakdee, S. Harashima, and Y. Oshima. (1996). Two new genes, PHO86 and PHO87, involved in inorganic phosphate uptake in Saccharomyces cerevisiae. Curr. Genet. 29: 344-351.
Chen, X.-Z., C. Shayakul, U.V. Berger, W. Tian, and M.A. Hediger. (1998). Characterization of a rat Na⁺-dicarboxylate cotransporter. J. Biol. Chem. 273: 29072-20981.
Estrella, L.A., S. Krishnamurthy, C.R. Timme, and M. Hampsey. (2008). The Rsp5 E3 ligase mediates turnover of low affinity phosphate transporters in Saccharomyces cerevisiae. J. Biol. Chem. 283: 5327-5334.
Fei, Y.-J., K. Inoue, and V. Ganapathy. (2003). Structural and functional characteristics of two sodium-coupled dicarboxylate transporters (ceNaDC1 and ceNaDC2) from Caenorhabditis elegans and their relevance to life span. J. Biol. Chem. 278: 6136-6144.
Hall, J.A., and Pajor A.M. (2007). Functional reconstitution of SdcS, a Na+-coupled dicarboxylate carrier protein from Staphylococcus aureus. J. Bacteriol. 189: 880-885.
Inoue, K., L. Zhuang, D.M. Maddox, S.B. Smith, and V. Ganapathy. (2002). Structure, function, and expression pattern of a novel sodium-coupled citrate transporter (NaCT) cloned from mammalian brain. J. Biol. Chem. 277: 39469-39476.
Inoue, K., Y.J. Fei, W. Huang, L. Zhuang, Z. Chen, and V. Ganapathy. (2002). Functional identity of Drosophila melanogaster Indy as a cation-independent, electroneutral transporter for tricarboxylic acid-cycle intermediates. Biochem. J. 367: 313-319.
Joshi, A.D. and A.M. Pajor. (2009). Identification of Conformationally Sensitive Amino Acids in the Na⁺/Dicarboxylate Symporter (SdcS) (dagger). Biochemistry 48: 3017-3024.
Kekuda, R., H.P. Wang, W. Huang, A.M. Pajor, F.H. Leibach, L.D. Devoe, P.D. Prasad, and V. Ganapathy. (1999). Primary structure and functional characteristics of a mammalian sodium-coupled high affinity dicarboxylate transporter. J. Biol. Chem. 274: 3422-3429.
Kim, O.B. and G. Unden. (2006). The L-Tartrate/Succinate antiporter TtdT (YgjE) of L-Tartrate fermentation in Escherichia coli. J. Bacteriol. 189(5): 1597-1603.
Kovermann, P., S. Meyer, S. Hörtensteiner, C. Picco, J. Scholz-Starke, S. Ravera, Y. Lee, and E. Martinoia. (2007). The Arabidopsis vacuolar malate channel is a member of the ALMT family. Plant J. 52: 1169-1180.
Li, H. and A.M. Pajor. (2003). Serines 260 and 288 are involved in sulfate transport by hNaSi-1. J. Biol. Chem. 278: 37204-37212.
Markovich, D., J. Forgo, G. Stange, J. Biber, and H. Murer. (1993). Expression cloning of rat renal Na⁺/SO₄^2- cotransport. Proc. Natl. Acad. Sci. USA 90: 8073-8077.
Morris, M.E. and H. Murer. (2001). Molecular mechanisms in renal and intestinal sulfate (re)absorption. J. Membrane Biol. 181: 1-9.
Pajor, A.M. (1995). Sequence and functional characterization of a renal sodium/dicarboxylate cotransporter. J. Biol. Chem. 270: 5779-5785.
Pajor, A.M. (1999). Sodium-coupled transporters for Krebs Cycle intermediates. Annu. Rev. Physiol. 61: 663-682.
Pajor, A.M. (2000). Molecular properties of sodium/dicarboxylate cotransporters. J. Membrane. Biol. 175: 1-8.
Pajor, A.M., N. Sun, L. Bai, D. Markovich, and P. Sule. (1997). The substrate recognition domain in the Na⁺/dicarboxylate and Na⁺/sulfate cotransporters is located in the carboxy-terminal portion of the protein. Biochim. Biophys. Acta 1370: 98-106.
Pootakham, W., D. Gonzalez-Ballester, and A.R. Grossman. (2010). Identification and regulation of plasma membrane sulfate transporters in chlamydomonas. Plant Physiol. 153: 1653-1668.
Pos, K.M., P. Dimroth, and M. Bott. (1998). The Escherichia coli citrate carrier CitT: a member of a novel eubacterial transporter family related to the 2-oxoglutarate/malate translocator from spinach chloroplasts. J. Bacteriol. 180: 4160-4165.
Rabus, R., D.L. Jack, D.J. Kelly, and M.H. Saier, Jr. (1999). TRAP transporters: an ancient family of periplasmic solute receptor-dependent secondary active transporters. Microbiology 145: 3431-3445.
Saier, M.H., Jr., B.H. Eng, S. Fard, J. Garg, D.A. Haggerty, W.J. Hutchinson, D.L. Jack, E.C. Lai, H.J. Liu, D.P. Nusinew, A.M. Omar, S.S. Pao, I.T. Paulsen, J.A. Quan, M. Sliwinski, T.-T. Tseng, S. Wachi, and G.B. Young. (1999). Phylogenetic characterization of novel transport protein families revealed by genome analyses. Biochim. Biophys. Acta 1422: 1-56.
Steffgen, J., B.C. Burckhardt, C. Langenberg, L. Kühne, G.A. Müller, G. Burckhardt, and N.A. Wolff. (1999). Expression cloning and characterization of a novel sodium-dicarboxylate cotransporter from winter flounder kidney. J. Biol. Chem. 274: 20191-20196.
Strickler, M.A., J.A. Hall, O. Gaiko, and A.M. Pajor. (2009). Functional characterization of a Na⁺-coupled dicarboxylate transporter from Bacillus licheniformis. Biochim. Biophys. Acta. [Epub: Ahead of Print]
Teramoto, H., T. Shirai, M. Inui, and H. Yukawa. (2008). Identification of a gene encoding a transporter essential for utilization of C4 dicarboxylates in Corynebacterium glutamicum. Appl. Environ. Microbiol. 74: 5290-5296.
Urbany, C. and H.E. Neuhaus. (2008). Citrate uptake into Pectobacterium atrosepticum is critical for bacterial virulence. Mol. Plant Microbe Interact. 21: 547-554.
Wada, M., A. Shimada, and T. Fujita. (2006). Functional characterization of Na⁺ -coupled citrate transporter NaC2/NaCT expressed in primary cultures of neurons from mouse cerebral cortex. Brain Res 1081: 92-100.
Wang, G., S.P. Kennedy, S. Fasiludeen, C. Rensing, and S. DasSarma. (2004). Arsenic resistance in Halobacterium sp. strain NRC-1 examined by using an improved gene knockout system. J. Bacteriol. 186: 3187-3194.
Weber, A., E. Menzlaff, B. Arbinger, M. Gutensohn, C. Eckerskorn, and U.-I. Flüge. (1995). The 2-oxoglutarate/malate translocator of chlorplast envelope membranes: molecular cloning of a transporter containing a 12-helix motif and expression of the functional protein in yeast cells. Biochemistry 34: 2621-2627.
Yodoya, E., M. Wada, A. Shimada, H. Katsukawa, N. Okada, A. Yamamoto, V. Ganapathy, and T. Fujita. (2006). Functional and molecular identification of sodium-coupled dicarboxylate transporters in rat primary cultured cerebrocortical astrocytes and neurons. J. Neurochem. 97: 162-173.
Examples:
TC#	Name	Organismal Type	Example
2.A.47.1.1	Anion transporter of unknown specificity	Archaea	*Anion transporter of Methanospirillum hungatei* (Q2FMC1)**

2.A.47.1.10	Cation-independent, electroneutral tri- and di-carboxylate transporter with a preference for tricarboxylates, Indy (I'm not dead yet) [When Indy is mutated flies live about twice as long as wild type] (Inoue et al., 2002)	Animals	*Indy of Drosophila melanogaster* (Q9VVT2)**

2.A.47.1.11	The Na⁺:dicarboxylate (2:1) symporter, SdcS (catalyzes succinate:succinate antiport as well as electroneutral symport in reconstituted proteoliposomes (Hall and Pajor, 2007; Joshi and Pajor, 2009)	Bacteria	*SdcS of Staphylococcus aureus* (Q2FFH9)**

2.A.47.1.12	*The aerobic dicarboxylate (succinate, fumarate, malate) transporter, DcsT (Teramoto et al., 2008).*	Bacteria	*DcsT of Corynebacterium glutamicum* (A4QAL6)**

2.A.47.1.13	*The Na⁺-coupled dicarboxylate transporter, SdcL (transports aspartate, α-ketoglutarate and oxaloacetate with low affinity) (Strickler et al., 2009).*	Bacteria	*SdcL of Bacillus licheniformis* (Q65NC0)**

2.A.47.1.2	Renal sodium:sulfate cotransporter (Ssc) (NaS₁-1) (also transports thiosulfate and selenate) (Li and Pajor, 2003)	Animals	Ssc of Rattus norvegicus

2.A.47.1.3	The brush boarder intestinal and renal electrogenic, Na⁺-dependent, low affinity (0.1-4.0mM), dicarboxylate (succinate, fumarate, malate, α-ketoglutarate, oxaloacetate, L- and D-glutamate, and citrate):H⁺ cotransporter, NaDC-1 or SDCT1.	Animals	*NaDC-1 or SDCT1 of Rattus norvegicus* (O35055)**

2.A.47.1.4	The basolateral intestinal and renal electrogenic, Na⁺-dependent high affinity (2-50µM) dicarboxylate:(Na⁺)₃ cotransporter (NaDC-3) (substrate range similar to that of NDC-1 except that tricarboxylates are transported with very low affinity). Na⁺:succinate = 3:1. Also transports N-acetyl-L-aspartate, an abundant amino acid in the nervous system (Yodoya et al., 2006).	Animals	NaDC-3 of Rattus norvegicus

2.A.47.1.5	Basolateral Na⁺: di- and tricarboxylate (succinate cis-aconitate, citrate, etc.) cotransporter, fNaDC-3	Animals	*fNaDC-3 of Pseudopleuronectes americanus* (the winter flounder)**

2.A.47.1.6	*The tonoplast dicarboxylate (malate) transporter, AttDT (Kovermann et al., 2007).*	Plants	AttDT of malate:Na⁺ symporter of Arabidopsis thaliana

2.A.47.1.7	*Low affinity dicarboxylate:Na⁺ symporter, NaDC1 (INDY1) (relative affinities: succinate > fumarate > α-ketoglutarate > malate > lactate > maleate) (Fei et al., 2003)*	Animals	NaDC1 of Caenorhabditis elegans

2.A.47.1.8	*High affinity dicarboxylate:Na⁺ symporter, NaDC2 (INDY2) (relative affinities: fumarate > malate > α-ketoglutarate > maleate > succinate > lactate) (Fei et al., 2003)*	Animals	NaDC2 of Caenorhabditis elegans

2.A.47.1.9	Na⁺-coupled citrate transporter (NaCT) (K_m=18μM) (also may transport dicarboxylates and other tricarboxylates with lower affinity) (Inoue et al., 2002). Na⁺:citrate = 3-4:1 (Wada et al., 2006).	Animals	NaCT of Homo sapiens

Examples:
TC#	Name	Organismal Type	Example
2.A.47.2.1	Inorganic phosphate transporter, Pho87	Yeast	Pho87 of Saccharomyces cerevisiae

2.A.47.2.2	*Vacuolar low affinity phosphate transporter, Pho91 (Estrella et al., 2008)*	Yeast	*Pho91 of Saccharomyces cerevisiae* (P27514)**

Examples:
TC#	Name	Organismal Type	Example
2.A.47.3.1	2-oxoglutarate:malate antiporter (SodiTl)	Plant chloroplasts	SodiTl of Spinacia oleracea

2.A.47.3.2	Citrate:succinate antiporter	Bacteria	*CitT of E. coli* (P0AE74)**

2.A.47.3.3	L-tartrate:succinate antiporter, TtdT (YgjE). (also takes up both L-tartrate and succinate; does not transport D-tartrate) (Kim and Unden, 2007).	Bacteria	*TtdT (YgjE) of E. coli* (P39414)**

2.A.47.3.4	The pmf-dependent citrate uptake system, Cit1 (Urbany and Neuhaus, 2008)	Bacteria	*Cit1 of Erwinia carotovora* subsp. atroseptica (Q6D017)**

Examples:
TC#	Name	Organismal Type	Example
2.A.47.4.1	Sulfur-deprivation response protein	Cyanobacteria	SdrP of Synechocystis

2.A.47.4.2	Antimonite resistance protein (inducible by both arsenite and antimonite although arsenite resistance was not detected)	Archaea	*ArsB of Halobacterium* spNRC-1 (AAG20642)**

2.A.47.4.3	*The Na⁺/sulfate symporter, Slt1 (Pootakham et al., 2010)*	Algae	*Slt1 of Chlamydomonas reinhardtii* (A8IJF8)**

2.A.47.4.4	*The Na⁺/sulfate symporter, Slt2 (Pootakham et al., 2010)*	Algae	*Slt2 of Chlamydomonas reinhardtii* (A8IHV5)**

Examples:
TC#	Name	Organismal Type	Example
2.A.47.5.1	Hypothetical Na⁺ cotransporter, Orfl	Archaea	Orfl of Methanococcus jannaschii