Table 1. Functional characteristics of the members of the SLC13 family in humans.

HUGO Name TCDB ID UniProt ID	Common name(s)	Substrates	Tissue expression	Chromosome location	Disease connection
SLC13A1 2.A.47.1.16 Q9BZW2	Na+/sulfate cotransporter NaS1	Sulfate Thiosulfate Selenate	Kidney (BBM)	7q31.31	None
SLC13A2 2.A.47.1.17 Q13183	Na+/dicarboxylate cotransporter (low affinity) NaDC1/NaC1	Succinate α-Ketoglutarate Fumarate Malate Citrate	Kidney (BBM) Intestine (BBM)	17q11.2	None
SLC13A3 2.A.47.1.15 Q8WWT9	Na+/dicarboxylate cotransporter (high-affinity) NaDC3/NaC3	Succinate α-Ketoglutarate Fumarate Malate Citrate	Kidney (BBM) Liver (SM/BLM) Placenta (BBM)	20q13.12	None
SLC13A4 2.A.47.1.14 Q9UKG4	Na+/sulfate cotransporter SUT1/NaS2	Sulfate	Placenta (BBM) Testis Heart	7q33	None
SLC13A5 2.A.47.1.9 Q86YT5	Na+/citrate cotransporter NaCT/NaC2	Citrate Succinate Pyruvate	Liver (SM/BLM) Brain (neuron) Testis (germ cell)	17p13.1	EIEE25 (DEE25) OMIM # 615905

BBM, lumen-facing brush-border membrane in kidney and intestinal epithelial cells and maternal-facing brush-border membrane in placental trophoblasts; SM/BLM, blood-facing sinusoidal membrane, also called basolateral membrane, in hepatocytes; SLC, solute-linked carrier; NaS, Na⁺/Sulfate cotransporter; NaDC, Na⁺/Dicarboxylate Cotransporter; SUT1, Sulfate Transporter; NaCT, Na⁺-coupled Citrate Transporter; NaC, Na⁺/Carboxylate transporter; EIEE25, Early Infantile Epileptic Encephalopathy-25; DEE25, Developmental Epileptic Encephalopathy; HUGO, Human Genome Organization; TCDB, Transporter Classification Database; UniProt, UniProt database for protein sequences; ID, Identification number. Each of the transporter is identified by its SLC classification according to the Human Genome Organization (e.g. SLC13A1) or by its transporter classification according to the Transporter Classification Database (e.g. 2.A.47.1.16) and the corresponding protein is identified by its amino acid sequence ID according to the UniProt database for protein sequences (e.g. Q9BZW2).