Research Report: Rat **Slc13a2 / NaDC1** (UniProt **P70545**) — Functional Annotation Falcon Edison Scientific Literature 33 citations 1 artifacts 2026-06-01T02:10:03.792687

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Research Report: Rat Slc13a2 / NaDC1 (UniProt P70545) — Functional Annotation

0) Target verification (critical identity check)

The provided UniProt accession P70545 corresponds to Slc13a2 in Rattus norvegicus and encodes solute carrier family 13 member 2, commonly termed NaDC1 / NADC‑1 / SDCT1, an apical Na+-coupled dicarboxylate (incl. citrate) cotransporter in kidney and intestine. The retrieved literature consistently equates SLC13A2/Slc13a2 with NaDC1/NADC‑1 and describes the expected epithelial localization and citrate/succinate substrate class, supporting that the correct gene/protein was researched. (yang2021slc26a6andnadc‑1 pages 3-5, romero2010snpsofmetabolism pages 1-2, calıskan2023theassociationbetween pages 3-4)

1) Key concepts and definitions (current understanding)

1.1 Gene family and conceptual role

Slc13a2 (NaDC1) is a member of the SLC13 / DASS (divalent anion sodium symporter) family of electrogenic sodium–anion cotransporters that couple the inward Na+ electrochemical gradient to uptake of di-/tricarboxylates (e.g., Krebs-cycle intermediates). (chi2024cryoemstructuresof pages 1-1, yang2021slc26a6andnadc‑1 pages 3-5)

1.2 Transported substrates (what it transports)

Across mammalian NaDC1 orthologs, NaDC1 shows preference for divalent Krebs-cycle anions, with high affinity for succinate and generally lower affinity for citrate; recent work and reviews describe NaDC1 as mediating Na+-dependent cotransport of citrate and succinate in kidney and intestine. (yang2021slc26a6andnadc‑1 pages 3-5, chi2024cryoemstructuresof pages 1-1)

1.3 Coupling and mechanism (how it transports)

NaDC1 is described as a Na+-coupled electrogenic symporter. A review synthesis reports a Na+:anion coupling ratio of 3:1, consistent with an electrogenic uptake process. (yang2021slc26a6andnadc‑1 pages 3-5)

Mechanistic paradigm (2024): elevator transport. High-resolution cryo-EM of human NaDC1 (SLC13A2) supports an elevator-type alternating-access mechanism, with a relatively stable scaffold/dimerization region and a mobile transport/core domain; protomers within the dimer can occupy different conformations, implying semi-independent transport cycles. (chi2024cryoemstructuresof pages 1-3, chi2024cryoemstructuresof pages 1-1)

2) Localization (tissues, cell types, and subcellular membrane domain)

2.1 Tissue distribution

NaDC1 is reported as widely expressed in kidney and gastrointestinal epithelium. (yang2021slc26a6andnadc‑1 pages 3-5)

2.2 Kidney (rat-relevant localization)

For rat, NaDC1 is described as localizing to the outer stripe of the outer medulla and to luminal membranes in the renal superficial cortex, consistent with proximal tubule apical/brush-border expression. (yang2021slc26a6andnadc‑1 pages 3-5)

2.3 Intestine

NaDC1 is discussed as an apical intestinal absorption pathway for citrate/dicarboxylates, complementing renal handling; a physiologic commentary notes that reduced gut NaDC1 activity would be expected to lower blood citrate and thus urinary citrate, although NaDC1 knockout mice reportedly have normal serum citrate, implying metabolic compensation. (romero2010snpsofmetabolism pages 1-2)

3) Core physiological functions and pathways

3.1 Proximal tubule citrate reabsorption and acid–base physiology

NaDC1 is repeatedly positioned as a primary apical entry step for citrate reabsorption in proximal tubule, thereby regulating how much citrate remains in urine versus being reclaimed and metabolized. In the Osis et al. physiology framework, reabsorbed citrate can be metabolized to yield bicarbonate equivalents, linking NaDC1-mediated citrate handling to systemic acid-base balance. (osis2019regulationofrenal pages 16-19)

A review synthesis further states that a major fraction of filtered citrate is reabsorbed in proximal tubule via NaDC1 (review includes a cited quantitative statement that “>65%” is reabsorbed via NADC‑1; the cited figure was derived from prior animal work). (yang2021slc26a6andnadc‑1 pages 3-5)

3.2 Stone biology linkage (why citrate matters)

Urinary citrate complexes Ca2+ and is widely considered protective against calcium stone formation; thus, increased citrate reabsorption via NaDC1 can contribute to hypocitraturia, a common risk factor in nephrolithiasis. One review reports ~50% of nephrolithiasis patients exhibit hypocitraturia (as a broad statistic). (yang2021slc26a6andnadc‑1 pages 3-5)

4) Regulation and interaction network (what modulates NaDC1)

4.1 Acid-base and potassium regulation

A kidney physiology study synthesizes earlier work indicating chronic metabolic acidosis increases NaDC‑1 mRNA and protein abundance in rat kidney, consistent with increased citrate reclamation during acid loads. (osis2019regulationofrenal pages 28-32)

Hypokalemia (modeled as a K+-free diet) decreases urinary citrate excretion and is accompanied by increased NaDC1 expression in specific proximal tubule segments in mouse, illustrating a conserved regulatory axis between K+ status and citrate handling. (osis2019regulationofrenal pages 16-19)

4.2 Segment-specific proximal tubule regulation (axial heterogeneity)

In mouse kidney, NaDC1 upregulation with acid loading and hypokalemia is emphasized in cortical proximal tubule segments (PCT and PST-MR) rather than PST-OM, suggesting spatially restricted regulatory mechanisms. (osis2019regulationofrenal pages 16-19)

4.3 NBCe1-A as an upstream regulator of NaDC1 expression and citrate excretion

Osis et al. show that deletion of NBCe1-A (a proximal-tubule basolateral Na+-HCO3− cotransporter variant) reduces NaDC1 expression in cortical proximal tubule segments and alters urinary citrate excretion responses to acid and K+ perturbations, positioning NBCe1-A as a major regulator of the NaDC1-dependent citrate handling phenotype. (osis2019regulationofrenal pages 16-19)

4.4 Protein–protein interaction: SLC26A6–NaDC1 complex

NaDC1 is functionally linked to SLC26A6, an epithelial anion exchanger important for oxalate handling. Review and primary evidence indicate that SLC26A6 and NaDC1 can mutually modulate activity, implying coordinated regulation of oxalate/citrate homeostasis. (yang2021slc26a6andnadc‑1 pages 3-5, shimshilashvili2020novelhumanpolymorphisms pages 3-4)

A review synthesis also reports that IRBIT can inhibit NaDC1-mediated succinate transport by ~50% in the SLC26A6/NADC‑1 complex context. (yang2021slc26a6andnadc‑1 pages 3-5)

5) Recent developments and latest research (prioritizing 2023–2024)

5.1 2024 structural biology breakthrough: NaDC1 cryo-EM and allosteric inhibition

Chi et al. (published March 2024) solved cryo-EM structures of human NaDC1 (SLC13A2), capturing citrate-bound outward-facing conformations and defining detailed substrate and Na+ coordination.

Key molecular insights:
- Citrate sits in a pocket at the scaffold–core interface with two Na+ sites resolved (Na1 and Na2). (chi2024cryoemstructuresof pages 1-3)
- Residues implicated in Na+/substrate coordination and transport include Ser140, Asn141, Thr142, Thr240, Thr471, Thr474, Asn476, Ala518, and Arg108; alanine substitutions at several of these sites markedly reduce citrate-induced currents. (chi2024cryoemstructuresof pages 1-3, chi2024cryoemstructuresof pages 5-7)
- The work supports an elevator mechanism and identifies an unexpected peripheral/allosteric inhibitor site for N-(p-amylcinnamoyl) anthranilic acid (ACA) near the cytosolic membrane (TM2/L10/TM11/TM6a), providing a concrete framework for inhibitor design against NaDC1. (chi2024cryoemstructuresof pages 3-5, chi2024cryoemstructuresof pages 1-1)

Publication details: Science Advances (2024-03). URL: https://doi.org/10.1126/sciadv.adl3685 (chi2024cryoemstructuresof pages 1-1)

5.2 2023 clinical genetics: SLC13A2 (NaDC1) polymorphism and urinary citrate

Çalışkan et al. (published October 2023) tested the association of rs11567842 (I550V) with urinary citrate in 96 calcium-stone patients, stratified into normocitraturia vs hypocitraturia groups.

Key quantitative findings:
- Normocitraturia (n=40): 773 ± 301 mg/1.73 m²/24 h citrate.
- Hypocitraturia (n=56): 152 ± 87 mg/1.73 m²/24 h citrate (p<0.001).
- Genotype frequencies (AA/AG/GG) did not differ significantly between groups (p=0.618). (calıskan2023theassociationbetween pages 3-4)

The authors conclude this polymorphism does not explain hypocitraturia in their cohort, underscoring that NaDC1-linked stone risk is likely multifactorial (diet, acid-base, other genes, regulation). URL: https://doi.org/10.4274/jus.galenos.2023.2023-10-2 (calıskan2023theassociationbetween pages 1-2, calıskan2023theassociationbetween pages 3-4)

6) Current applications and real-world implementations

6.1 Nephrolithiasis risk stratification and mechanistic biomarkers

Because NaDC1 is directly linked to urinary citrate handling, it is frequently discussed as a mechanistic node in hypocitraturia-associated calcium stone disease (risk stratification and mechanistic interpretation of low urinary citrate). (yang2021slc26a6andnadc‑1 pages 3-5)

6.2 Tissue expression as a clinical correlate

In nephrolithiasis patients, intrarenal NaDC-1 expression categories (weak/intermediate/high by immunostaining) were associated with urine pH (inverse correlation; Spearman r = −0.516, p = 0.010), supporting the concept that acidified urinary environment or systemic acid-base state associates with higher NaDC1 expression. (chuaypen2013increasedintrarenalexpression pages 2-5)

6.3 Drug discovery and therapeutic targeting opportunities

The 2024 structural identification of an ACA inhibitor binding site and lipid-associated modulation offers a tangible structure-guided drug design foundation to modulate NaDC1 activity (conceptually: increasing urinary citrate by inhibiting apical uptake, or modulating uptake in metabolic contexts). (chi2024cryoemstructuresof pages 3-5, chi2024cryoemstructuresof pages 5-7)

7) Expert opinions and analysis (authoritative synthesis)

7.1 Complexity of genotype-to-phenotype mapping

A renal physiology commentary argues that common NaDC1 allelic variants are unlikely to be sole drivers of hypocitraturia or nephrolithiasis, given compensatory metabolic citrate production and multi-step handling of citrate by intestine, kidney, and metabolism. This aligns with later clinical findings where a common NaDC1 SNP did not segregate with hypocitraturia in one cohort. (romero2010snpsofmetabolism pages 1-2, calıskan2023theassociationbetween pages 3-4)

7.2 Network view of oxalate/citrate homeostasis

A review synthesizes that NaDC1 should be interpreted within an epithelial transport network involving SLC26A6 (oxalate handling) and regulatory proteins (e.g., IRBIT), linking citrate reclamation, succinate signaling, and potentially blood pressure phenotypes in addition to stone risk. (yang2021slc26a6andnadc‑1 pages 3-5)

8) Key statistics and data (recent and/or quantitative)

8.1 Mouse renal physiology: hypokalemia and NaDC1-linked citrate excretion

Osis et al. (2019) quantify urinary citrate excretion changes:
- WT: 72 ± 10.6 µmol/day → 3.3 ± 2.4 µmol/day on K+-free diet (n=6; P<0.001).
- NBCe1-A KO: 96 ± 21.0 µmol/day basal (n=6; P<0.05 vs WT) → 16.6 ± 8.9 µmol/day on K+-free diet (n=6; P<0.001 vs K+-control).
- Percent decrease in citrate excretion: WT 95% ± 3% vs KO 83% ± 6% (P<0.002; n=6). (osis2019regulationofrenal pages 16-19)

URL: https://doi.org/10.1152/ajprenal.00015.2019 (osis2019regulationofrenal pages 16-19)

8.2 Human cohort: citrate values and NaDC1 SNP frequencies (2023)

As above (Section 5.2), Çalışkan et al. (2023) provide clear quantitative separation between normocitraturia and hypocitraturia in stone formers and report AA/AG/GG genotype counts for rs11567842. (calıskan2023theassociationbetween pages 3-4)

8.3 Nephrolithiasis tissue study: NaDC-1 expression vs urine pH

In 24 nephrolithiasis patients, NaDC-1 expression distribution was weak 25% (6/24), intermediate 42% (10/24), high 33% (8/24), with significantly lower urine pH in the high-expression group and a significant inverse correlation (Spearman r = −0.516, p = 0.010). (chuaypen2013increasedintrarenalexpression pages 2-5)

9) Summary functional annotation (rat Slc13a2 / UniProt P70545)

Primary molecular function. Rat Slc13a2 encodes NaDC1, an apical epithelial Na+-coupled symporter for dicarboxylates (notably succinate) and citrate, supporting uptake of Krebs-cycle intermediates in kidney proximal tubule and intestine, with a commonly cited electrogenic 3 Na+:1 anion coupling ratio. (yang2021slc26a6andnadc‑1 pages 3-5, chi2024cryoemstructuresof pages 1-1)

Cellular and tissue localization. In rat kidney, NaDC1 localizes to luminal/apical membranes in superficial cortex proximal tubule and to the outer stripe of the outer medulla, consistent with proximal tubule segment expression; it is also present in gastrointestinal epithelium. (yang2021slc26a6andnadc‑1 pages 3-5)

Physiological role. By reclaiming filtered citrate, NaDC1 regulates urinary citrate (a key modulator of calcium stone risk) and participates in acid-base physiology through citrate metabolism to bicarbonate equivalents. (osis2019regulationofrenal pages 16-19, yang2021slc26a6andnadc‑1 pages 3-5)

Regulation. Acid-base status and potassium balance modulate NaDC1 expression and citrate excretion phenotypes; NaDC1 is embedded in a regulatory network involving NBCe1-A and SLC26A6 (and in review synthesis, IRBIT), which coordinates citrate and oxalate handling relevant to nephrolithiasis. (osis2019regulationofrenal pages 28-32, osis2019regulationofrenal pages 16-19, yang2021slc26a6andnadc‑1 pages 3-5)

State of the art (2024). Cryo-EM structures of NaDC1 define an elevator mechanism, pinpoint substrate/Na+ coordination residues, and reveal an allosteric inhibitor pocket (ACA), enabling structure-guided pharmacology that could be leveraged to modulate urinary citrate handling and related phenotypes. (chi2024cryoemstructuresof pages 1-3, chi2024cryoemstructuresof pages 3-5, chi2024cryoemstructuresof pages 1-1)

Artifact: evidence-backed summary table

Aspect Key points Species/context (rat vs human vs mouse) Key sources (with year, journal, DOI/URL)
Verified identity Rat Slc13a2 corresponds to NaDC1 / Na(+)-dicarboxylate cotransporter 1, a member of the SLC13/DASS family. Gathered evidence consistently treats SLC13A2/NaDC1/NADC-1/SDCT1 as the renal/intestinal sodium-coupled dicarboxylate transporter relevant to citrate/succinate transport; this matches the UniProt P70545 description for Rattus norvegicus. Rat identity supported by rat-localization/review evidence; human and mouse papers are orthologous context used for mechanism and physiology. Yang et al., 2021, Molecular Medicine Reports, doi:10.3892/mmr.2021.12385, https://doi.org/10.3892/mmr.2021.12385; Osis et al., 2019, Am J Physiol Renal Physiol, doi:10.1152/ajprenal.00015.2019, https://doi.org/10.1152/ajprenal.00015.2019 (yang2021slc26a6andnadc‑1 pages 3-5, osis2019regulationofrenal pages 32-36)
Protein architecture/family NaDC1 is described as an 11-transmembrane helix transporter in the SLC13/DASS family, with intracellular N-terminus and extracellular C-terminus and conserved N-glycosylation features. Architecture summarized mainly from human-focused review, but applied to mammalian NaDC1 orthologs including rat. Yang et al., 2021, Molecular Medicine Reports, doi:10.3892/mmr.2021.12385, https://doi.org/10.3892/mmr.2021.12385 (yang2021slc26a6andnadc‑1 pages 3-5)
Main substrates Preferred substrates are divalent Krebs-cycle/dicarboxylate anions, especially succinate (high affinity), with citrate also transported but generally at lower affinity; NaDC1 is broadly discussed as mediating Na+-dependent cotransport of citrate and succinate. Rat review/localization evidence plus human structural and clinical context. Yang et al., 2021, Molecular Medicine Reports, doi:10.3892/mmr.2021.12385, https://doi.org/10.3892/mmr.2021.12385; Chi et al., 2024, Science Advances, doi:10.1126/sciadv.adl3685, https://doi.org/10.1126/sciadv.adl3685; Shimshilashvili et al., 2020, Front Pharmacol, doi:10.3389/fphar.2020.00405, https://doi.org/10.3389/fphar.2020.00405 (yang2021slc26a6andnadc‑1 pages 3-5, shimshilashvili2020novelhumanpolymorphisms pages 2-3, chi2024cryoemstructuresof pages 1-1)
Coupling/stoichiometry NaDC1 is an electrogenic Na+-coupled symporter. Review evidence states a 3 Na+:1 anion coupling ratio; one commentary excerpt notes 2 Na+-succinate cotransport in the context of variant discussion, so stoichiometry in the gathered evidence is not entirely uniform. The strongest explicit stoichiometric statement in the evidence base is 3:1. 3:1 ratio from review/general mammalian context; variant commentary not rat-specific. Yang et al., 2021, Molecular Medicine Reports, doi:10.3892/mmr.2021.12385, https://doi.org/10.3892/mmr.2021.12385; Romero, 2010, Am J Physiol Renal Physiol, doi:10.1152/ajprenal.00432.2010, https://doi.org/10.1152/ajprenal.00432.2010 (yang2021slc26a6andnadc‑1 pages 3-5, romero2010snpsofmetabolism pages 1-2)
Transport mechanism Recent structural work supports an elevator-type transport mechanism with a stable scaffold/dimerization domain and a mobile core domain. Human NaDC1 cryo-EM structures captured apo, citrate-bound, and inhibitor-bound outward-facing states; protomers can adopt different conformations, suggesting largely independent transport cycles within the dimer. Mechanism shown directly for human SLC13A2/NaDC1; relevant by homology to rat Slc13a2. Chi et al., 2024, Science Advances, doi:10.1126/sciadv.adl3685, https://doi.org/10.1126/sciadv.adl3685 (chi2024cryoemstructuresof pages 1-3, chi2024cryoemstructuresof pages 3-5, chi2024cryoemstructuresof pages 5-7, chi2024cryoemstructuresof pages 1-1)
Substrate/ion recognition Human NaDC1 structures place citrate in a pocket at the scaffold-core interface with two Na+ sites (Na1, Na2). Key residues implicated in transport/substrate recognition include Ser140, Asn141, Thr142, Thr240, Thr471, Thr474, Asn476, Ala518, and Arg108; mutagenesis reduced citrate-induced currents. Direct evidence from human NaDC1 structural/functional study; used here as current mechanistic understanding for the orthologous transporter family. Chi et al., 2024, Science Advances, doi:10.1126/sciadv.adl3685, https://doi.org/10.1126/sciadv.adl3685 (chi2024cryoemstructuresof pages 1-3, chi2024cryoemstructuresof pages 3-5, chi2024cryoemstructuresof pages 5-7)
Tissue localization NaDC1 is widely expressed in kidney and gastrointestinal epithelium. In rat, evidence places it in the outer stripe of the outer medulla and luminal membranes of the superficial renal cortex. Human clinical genetics review also notes expression in renal proximal tubule and small intestinal cells. Rat-specific localization available; human expression used as orthologous corroboration. Yang et al., 2021, Molecular Medicine Reports, doi:10.3892/mmr.2021.12385, https://doi.org/10.3892/mmr.2021.12385; Çalışkan et al., 2023, Journal of Urological Surgery, doi:10.4274/jus.galenos.2023.2023-10-2, https://doi.org/10.4274/jus.galenos.2023.2023-10-2 (yang2021slc26a6andnadc‑1 pages 3-5, calıskan2023theassociationbetween pages 3-4)
Subcellular localization NaDC1 localizes to the apical/luminal (brush-border) membrane of proximal tubule epithelial cells and is also discussed as apical in intestine/small intestinal villus epithelium. Rat apical kidney localization supported directly; intestinal/apical context supported by review and human study. Yang et al., 2021, Molecular Medicine Reports, doi:10.3892/mmr.2021.12385, https://doi.org/10.3892/mmr.2021.12385; Romero, 2010, Am J Physiol Renal Physiol, doi:10.1152/ajprenal.00432.2010, https://doi.org/10.1152/ajprenal.00432.2010; Çalışkan et al., 2023, Journal of Urological Surgery, doi:10.4274/jus.galenos.2023.2023-10-2, https://doi.org/10.4274/jus.galenos.2023.2023-10-2 (yang2021slc26a6andnadc‑1 pages 3-5, yang2021slc26a6andnadc‑1 pages 2-3, romero2010snpsofmetabolism pages 1-2, calıskan2023theassociationbetween pages 1-2, calıskan2023theassociationbetween pages 3-4)
Segment-specific renal expression/regulation In mouse kidney, NaDC1 expression is highest/adaptive in cortical proximal tubule segments (PCT and PST-MR), with less response in PST-OM; this demonstrates axial heterogeneity in regulation. Mouse regulation study; relevant physiological context for mammalian NaDC1, not direct rat measurement. Osis et al., 2019, Am J Physiol Renal Physiol, doi:10.1152/ajprenal.00015.2019, https://doi.org/10.1152/ajprenal.00015.2019 (osis2019regulationofrenal pages 28-32, osis2019regulationofrenal pages 16-19)
Regulation by acid-base status Gathered evidence cites that chronic metabolic acidosis increases NaDC1 mRNA and protein abundance in rat kidney and that acid loading alters citrate transport and NaDC1 expression/activity in proximal tubule. Rat cited in review of prior literature; mouse experimental support for acid-loading response. Osis et al., 2019, Am J Physiol Renal Physiol, doi:10.1152/ajprenal.00015.2019, https://doi.org/10.1152/ajprenal.00015.2019 (osis2019regulationofrenal pages 32-36, osis2019regulationofrenal pages 28-32, osis2019regulationofrenal pages 16-19)
Regulation by potassium status Hypokalemia / K+-free diet increases NaDC1 expression in cortical proximal tubule segments and decreases urinary citrate excretion; older literature cited in the evidence notes chronic potassium depletion stimulates the renal brush-border Na-citrate cotransporter. Direct experimental evidence in mouse; rat cited via prior literature in review/discussion. Osis et al., 2019, Am J Physiol Renal Physiol, doi:10.1152/ajprenal.00015.2019, https://doi.org/10.1152/ajprenal.00015.2019 (osis2019regulationofrenal pages 32-36, osis2019regulationofrenal pages 28-32, osis2019regulationofrenal pages 16-19)
Key regulator: NBCe1-A NBCe1-A is necessary for normal basal and adaptive renal citrate handling; its deletion reduces NaDC1 expression in cortical proximal tubule, increases urinary citrate excretion, and blunts hypokalemia-induced NaDC1 upregulation. Demonstrated in mouse; mechanistically relevant to renal NaDC1 regulation. Osis et al., 2019, Am J Physiol Renal Physiol, doi:10.1152/ajprenal.00015.2019, https://doi.org/10.1152/ajprenal.00015.2019 (osis2019regulationofrenal pages 32-36, osis2019regulationofrenal pages 28-32, osis2019regulationofrenal pages 16-19)
Key interacting protein: SLC26A6 NaDC1 functionally and physically interacts with SLC26A6. Evidence supports bidirectional modulation, with SLC26A6 restricting NaDC1 activity and thereby contributing to coordinated oxalate/citrate homeostasis relevant to stone risk. Mechanistic evidence primarily human/cell systems and review synthesis; kidney relevance broadly mammalian. Ohana et al., 2013, JASN, doi:10.1681/ASN.2013010080, https://doi.org/10.1681/ASN.2013010080; Shimshilashvili et al., 2020, Front Pharmacol, doi:10.3389/fphar.2020.00405, https://doi.org/10.3389/fphar.2020.00405; Yang et al., 2021, Molecular Medicine Reports, doi:10.3892/mmr.2021.12385, https://doi.org/10.3892/mmr.2021.12385 (yang2021slc26a6andnadc‑1 pages 3-5, shimshilashvili2020novelhumanpolymorphisms pages 2-3, shimshilashvili2020novelhumanpolymorphisms pages 3-4)
Additional modulators Gathered evidence cites regulation of NaDC1 by protein kinase C, NHERF2, SGK isoforms, protein kinase B, cyclophilin B (biogenesis), and endothelin B receptor dependence for acid regulation. IRBIT inhibits NaDC1-mediated succinate transport by about 50% in the SLC26A6/NaDC1 context. Mostly prior literature summarized in mouse/human reviews rather than rat-specific direct assays in the retrieved text. Osis et al., 2019, Am J Physiol Renal Physiol, doi:10.1152/ajprenal.00015.2019, https://doi.org/10.1152/ajprenal.00015.2019; Yang et al., 2021, Molecular Medicine Reports, doi:10.3892/mmr.2021.12385, https://doi.org/10.3892/mmr.2021.12385 (osis2019regulationofrenal pages 32-36, osis2019regulationofrenal pages 28-32, yang2021slc26a6andnadc‑1 pages 3-5)
Physiological role in kidney NaDC1 is the primary renal apical citrate reabsorption pathway discussed in the evidence base, mediating a major portion of filtered citrate reclamation in proximal tubule and thereby influencing systemic acid-base handling because metabolized citrate yields bicarbonate equivalents. Rat/human/mouse physiology synthesized across studies; one review cites >65% citrate reabsorption after filtration from rabbit data. Yang et al., 2021, Molecular Medicine Reports, doi:10.3892/mmr.2021.12385, https://doi.org/10.3892/mmr.2021.12385; Osis et al., 2019, Am J Physiol Renal Physiol, doi:10.1152/ajprenal.00015.2019, https://doi.org/10.1152/ajprenal.00015.2019 (yang2021slc26a6andnadc‑1 pages 3-5, osis2019regulationofrenal pages 16-19)
Disease/clinical link: nephrolithiasis By lowering urinary citrate when reabsorption is increased, NaDC1 is linked to hypocitraturia and thus to risk of calcium oxalate/calcium-containing kidney stones, since citrate inhibits Ca2+ stone formation. Increased intrarenal NaDC1 expression has been reported in stone formers with acidic urine, and SLC26A6–NaDC1 dysregulation may further increase lithogenic risk. Human disease relevance strongest; rat/mouse data mainly mechanistic. Çalışkan et al., 2023, Journal of Urological Surgery, doi:10.4274/jus.galenos.2023.2023-10-2, https://doi.org/10.4274/jus.galenos.2023.2023-10-2; Yang et al., 2021, Molecular Medicine Reports, doi:10.3892/mmr.2021.12385, https://doi.org/10.3892/mmr.2021.12385; Chi et al., 2024, Science Advances, doi:10.1126/sciadv.adl3685, https://doi.org/10.1126/sciadv.adl3685 (yang2021slc26a6andnadc‑1 pages 3-5, chi2024cryoemstructuresof pages 1-1, calıskan2023theassociationbetween pages 1-2, calıskan2023theassociationbetween pages 3-4)
Recent 2023 genetic study In a 2023 cohort of 96 calcium stone patients, urinary citrate differed markedly between normocitraturic and hypocitraturic groups, but rs11567842 (I550V) genotype frequencies did not differ significantly; this study concluded that this SNP alone did not explain hypocitraturia. Human clinical genetics; useful for disease relevance but not direct rat annotation. Çalışkan et al., 2023, Journal of Urological Surgery, doi:10.4274/jus.galenos.2023.2023-10-2, https://doi.org/10.4274/jus.galenos.2023.2023-10-2 (calıskan2023theassociationbetween pages 1-2, calıskan2023theassociationbetween pages 3-4)
Recent 2024 structural advance 2024 cryo-EM work is the key recent advance: it resolved human NaDC1 with citrate-bound and ACA inhibitor-bound states, identified an allosteric/peripheral inhibitor site near the cytosolic membrane, and provided a framework for future drug design targeting NaDC1. Human structural biology; strong mechanistic relevance for rat ortholog inference. Chi et al., 2024, Science Advances, doi:10.1126/sciadv.adl3685, https://doi.org/10.1126/sciadv.adl3685 (chi2024cryoemstructuresof pages 1-3, chi2024cryoemstructuresof pages 3-5, chi2024cryoemstructuresof pages 5-7, chi2024cryoemstructuresof pages 1-1)

Table: This table summarizes the verified identity, transport properties, localization, regulation, and physiological relevance of rat Slc13a2/NaDC1 using only claims supported by the gathered evidence. It also distinguishes rat-specific observations from human and mouse ortholog evidence used to interpret current functional annotation.

Limitations of this evidence set

References

  1. (yang2021slc26a6andnadc‑1 pages 3-5): Xingyue Yang, Shun Yao, Jiaxing An, Hai Jin, Hui Wang, and Biguang Tuo. Slc26a6 and nadc‑1: future direction of nephrolithiasis and calculus‑related hypertension research (review). Molecular medicine reports, Nov 2021. URL: https://doi.org/10.3892/mmr.2021.12385, doi:10.3892/mmr.2021.12385. This article has 7 citations and is from a peer-reviewed journal.

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  3. (calıskan2023theassociationbetween pages 3-4): Ahmet Çalışkan, Ömür Memik, Selma Düzenli, and Ali Tekin. The association between sodium citrate cotransporter (nadc-1) gene polymorphism and urinary citrate excretion in patients with calcium-containing kidney stone. Journal of Urological Surgery, Oct 2023. URL: https://doi.org/10.4274/jus.galenos.2023.2023-10-2, doi:10.4274/jus.galenos.2023.2023-10-2. This article has 1 citations.

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  8. (shimshilashvili2020novelhumanpolymorphisms pages 3-4): Liana Shimshilashvili, Sara Aharon, Orson W. Moe, and Ehud Ohana. Novel human polymorphisms define a key role for the slc26a6-stas domain in protection from ca2+-oxalate lithogenesis. Frontiers in Pharmacology, Apr 2020. URL: https://doi.org/10.3389/fphar.2020.00405, doi:10.3389/fphar.2020.00405. This article has 14 citations.

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  10. (chi2024cryoemstructuresof pages 3-5): Ximin Chi, Yiming Chen, Yaning Li, Lu Dai, Yuanyuan Zhang, Yaping Shen, Yun Chen, Tianhao Shi, Haonan Yang, Zilong Wang, and Renhong Yan. Cryo-em structures of the human nas1 and nadc1 transporters revealed the elevator transport and allosteric regulation mechanism. Science Advances, Mar 2024. URL: https://doi.org/10.1126/sciadv.adl3685, doi:10.1126/sciadv.adl3685. This article has 13 citations and is from a highest quality peer-reviewed journal.

  11. (calıskan2023theassociationbetween pages 1-2): Ahmet Çalışkan, Ömür Memik, Selma Düzenli, and Ali Tekin. The association between sodium citrate cotransporter (nadc-1) gene polymorphism and urinary citrate excretion in patients with calcium-containing kidney stone. Journal of Urological Surgery, Oct 2023. URL: https://doi.org/10.4274/jus.galenos.2023.2023-10-2, doi:10.4274/jus.galenos.2023.2023-10-2. This article has 1 citations.

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  13. (osis2019regulationofrenal pages 32-36): Gunars Osis, Kierstin L. Webster, Autumn N. Harris, Hyun-Wook Lee, Chao Chen, Lijuan Fang, Michael F. Romero, Ram B. Khattri, Matthew E. Merritt, Jill W. Verlander, and I. David Weiner. Regulation of renal nadc1 expression and citrate excretion by nbce1-a. American Journal of Physiology-Renal Physiology, 317:F489-F501, Aug 2019. URL: https://doi.org/10.1152/ajprenal.00015.2019, doi:10.1152/ajprenal.00015.2019. This article has 27 citations and is from a peer-reviewed journal.

  14. (shimshilashvili2020novelhumanpolymorphisms pages 2-3): Liana Shimshilashvili, Sara Aharon, Orson W. Moe, and Ehud Ohana. Novel human polymorphisms define a key role for the slc26a6-stas domain in protection from ca2+-oxalate lithogenesis. Frontiers in Pharmacology, Apr 2020. URL: https://doi.org/10.3389/fphar.2020.00405, doi:10.3389/fphar.2020.00405. This article has 14 citations.

  15. (yang2021slc26a6andnadc‑1 pages 2-3): Xingyue Yang, Shun Yao, Jiaxing An, Hai Jin, Hui Wang, and Biguang Tuo. Slc26a6 and nadc‑1: future direction of nephrolithiasis and calculus‑related hypertension research (review). Molecular medicine reports, Nov 2021. URL: https://doi.org/10.3892/mmr.2021.12385, doi:10.3892/mmr.2021.12385. This article has 7 citations and is from a peer-reviewed journal.

Artifacts

Citations

  1. romero2010snpsofmetabolism pages 1-2
  2. osis2019regulationofrenal pages 16-19
  3. osis2019regulationofrenal pages 28-32
  4. chi2024cryoemstructuresof pages 1-3
  5. chi2024cryoemstructuresof pages 1-1
  6. calıskan2023theassociationbetween pages 3-4
  7. chuaypen2013increasedintrarenalexpression pages 2-5
  8. shimshilashvili2020novelhumanpolymorphisms pages 3-4
  9. chi2024cryoemstructuresof pages 5-7
  10. chi2024cryoemstructuresof pages 3-5
  11. calıskan2023theassociationbetween pages 1-2
  12. osis2019regulationofrenal pages 32-36
  13. shimshilashvili2020novelhumanpolymorphisms pages 2-3
  14. https://doi.org/10.1126/sciadv.adl3685
  15. https://doi.org/10.4274/jus.galenos.2023.2023-10-2
  16. https://doi.org/10.1152/ajprenal.00015.2019
  17. https://doi.org/10.3892/mmr.2021.12385;
  18. https://doi.org/10.3892/mmr.2021.12385
  19. https://doi.org/10.1126/sciadv.adl3685;
  20. https://doi.org/10.3389/fphar.2020.00405
  21. https://doi.org/10.1152/ajprenal.00432.2010
  22. https://doi.org/10.1152/ajprenal.00432.2010;
  23. https://doi.org/10.1681/ASN.2013010080;
  24. https://doi.org/10.3389/fphar.2020.00405;
  25. https://doi.org/10.1152/ajprenal.00015.2019;
  26. https://doi.org/10.4274/jus.galenos.2023.2023-10-2;
  27. https://doi.org/10.3892/mmr.2021.12385,
  28. https://doi.org/10.1152/ajprenal.00432.2010,
  29. https://doi.org/10.4274/jus.galenos.2023.2023-10-2,
  30. https://doi.org/10.1126/sciadv.adl3685,
  31. https://doi.org/10.1152/ajprenal.00015.2019,
  32. https://doi.org/10.3389/fphar.2020.00405,
  33. https://doi.org/10.5372/1905-7415.0704.214,