GO_REF:0000002

GO reference used by source annotation pipeline

Source annotation pipeline provenance; biological support was assessed from UniProt and cached literature where available.

"GO_REF entry used to trace source annotation method rather than as primary biological evidence."

GO_REF:0000033

GO reference used by source annotation pipeline

Source annotation pipeline provenance; biological support was assessed from UniProt and cached literature where available.

"GO_REF entry used to trace source annotation method rather than as primary biological evidence."

GO_REF:0000107

GO reference used by source annotation pipeline

Source annotation pipeline provenance; biological support was assessed from UniProt and cached literature where available.

"GO_REF entry used to trace source annotation method rather than as primary biological evidence."

GO_REF:0000108

GO reference used by source annotation pipeline

Source annotation pipeline provenance; biological support was assessed from UniProt and cached literature where available.

"GO_REF entry used to trace source annotation method rather than as primary biological evidence."

GO_REF:0000117

GO reference used by source annotation pipeline

Source annotation pipeline provenance; biological support was assessed from UniProt and cached literature where available.

"GO_REF entry used to trace source annotation method rather than as primary biological evidence."

GO_REF:0000120

GO reference used by source annotation pipeline

Source annotation pipeline provenance; biological support was assessed from UniProt and cached literature where available.

"GO_REF entry used to trace source annotation method rather than as primary biological evidence."

GO_REF:0000121

GO reference used by source annotation pipeline

Source annotation pipeline provenance; biological support was assessed from UniProt and cached literature where available.

"GO_REF entry used to trace source annotation method rather than as primary biological evidence."

PMID:9691021

Cloning, functional characterization, and localization of a rat renal Na+-dicarboxylate transporter.

Rat Slc13a2/rNaDC-1 mediates sodium-dependent uptake of dicarboxylates and localizes to the apical/luminal membrane.

"Cloning, functional characterization, and localization of a rat renal Na+-dicarboxylate transporter."

PMID:9694847

Characterization of a rat Na+-dicarboxylate cotransporter.

Rat SDCT1/Slc13a2 mediates electrogenic sodium-dependent transport of Krebs-cycle intermediates.

"Characterization of a rat Na+-dicarboxylate cotransporter."

file:rat/Slc13a2/Slc13a2-deep-research-falcon.md

Falcon (Edison Scientific) deep research report: rat Slc13a2 / NaDC1 (UniProt P70545) functional annotation

Identity and core molecular function confirmed as an apical Na+-coupled dicarboxylate/citrate cotransporter (NaDC1) in kidney and intestine, matching UniProt P70545.

"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."
NaDC1 is an electrogenic Na+-coupled symporter with a commonly cited 3 Na+:1 anion coupling ratio, supporting the sodium:dicarboxylate symporter molecular function.

"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."
Substrate preference is for divalent Krebs-cycle anions, with high affinity for succinate and lower affinity for citrate, supporting the substrate-specific transporter terms.

"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."
Subcellular localization is the apical/luminal brush-border membrane of proximal tubule epithelial cells (and apical intestine), supporting apical plasma membrane as non-core 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-specific renal localization places NaDC1 in the outer stripe of the outer medulla and luminal membranes of the superficial cortex proximal tubule.

"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**."
Physiological role is primary apical citrate reabsorption in the proximal tubule, the pathway-level consequence of the transporter activity.

"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."
Mechanism is elevator-type alternating access, established by 2024 cryo-EM of human NaDC1 (SLC13A2) and applicable by orthology to the rat protein.

"**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."