SLC4A4

This gene encodes a sodium bicarbonate cotransporter (NBC) involved in the regulation of bicarbonate secretion and absorption and intracellular pH. Mutations in this gene are associated with proximal renal tubular acidosis. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq]

Full Name

solute carrier family 4, sodium bicarbonate cotransporter, member 4

Function

Electrogenic sodium/bicarbonate cotransporter with a Na+:HCO3- stoichiometry varying from 1:2 to 1:3. May regulate bicarbonate influx/efflux at the basolateral membrane of cells and regulate intracellular pH.

Biological Process

Biological Process bicarbonate transportManual Assertion Based On ExperimentIDA:ARUK-UCL
Biological Process ion homeostasisManual Assertion Based On ExperimentIBA:GO_Central
Biological Process positive regulation of glycolytic processManual Assertion Based On ExperimentIGI:ARUK-UCL
Biological Process regulation of intracellular pHManual Assertion Based On ExperimentIDA:ARUK-UCL
Biological Process regulation of membrane potentialManual Assertion Based On ExperimentIDA:ARUK-UCL
Biological Process sodium ion export across plasma membraneManual Assertion Based On ExperimentIMP:ARUK-UCL
Biological Process sodium ion transmembrane transportManual Assertion Based On ExperimentIDA:ARUK-UCL
Biological Process sodium ion transportManual Assertion Based On ExperimentIDA:UniProtKB
Biological Process transmembrane transportManual Assertion Based On ExperimentIMP:ARUK-UCL
Biological Process transport across blood-brain barrier1 PublicationNAS:ARUK-UCL

Cellular Location

Basolateral cell membrane
Cell membrane

Involvement in disease

Renal tubular acidosis, proximal, with ocular abnormalities and intellectual disability (pRTA-OA):
An extremely rare autosomal recessive syndrome characterized by short stature, profound proximal renal tubular acidosis, intellectual disability, bilateral glaucoma, cataracts and bandkeratopathy. pRTA is due to a failure of the proximal tubular cells to reabsorb filtered bicarbonate from the urine, leading to urinary bicarbonate wasting and subsequent acidemia.

PTM

Phosphorylation of Ser-1026 by PKA increases the binding of CA2 and changes the Na+:HCO3- stoichiometry of the transporter from 3:1 to 2:1 (PubMed:11744745, PubMed:12411514, PubMed:12730338).
Phosphorylated in presence of STK39 and dephosphorylated in presence of PP1 phosphatase; phosphorylation seems to inhibit SLC4A4 activity (By similarity).
N-glycosylated. May not be necessary for the transporter basic functions.