Electrogenic sodium bicarbonate cotransporter 1 (NBCe1) (SLC4A4)

Electrogenic sodium bicarbonate cotransporter 1 (SLC4A4), also known as NBCe1, is a transmembrane protein that mediates the coupled movement of sodium and bicarbonate ions across cell membranes, typically in a 1:2 or 1:3 stoichiometry [1]. It is a key regulator of both intracellular and extracellular pH, playing a vital role in systemic acid-base homeostasis, particularly within the renal proximal tubules where it facilitates the reabsorption of filtered bicarbonate back into the blood [1][2]. Mutations in the SLC4A4 gene are linked to autosomal recessive proximal renal tubular acidosis (pRTA), a condition characterized by metabolic acidosis, growth retardation, and ocular abnormalities such as glaucoma and cataracts [3][4]. In addition to its renal functions, SLC4A4 is expressed in the brain, pancreas, and eyes, contributing to fluid secretion and pH maintenance in these tissues [2][5]. From a therapeutic perspective, SLC4A4 is considered a potential target for treating diseases involving pH dysregulation, including certain cancers where it helps maintain the alkaline intracellular environment necessary for tumor cell survival and metastasis [6]. While experimental inhibitors like S0859 exist, the development of clinical therapeutics is complicated by the risk of systemic metabolic disturbances and the need for high isoform selectivity [1][7]. Sources: [1] UniProt (Q9Y6R1); [2] Boron, W. F. (2006) Physiol Rev; [3] Igarashi, T., et al. (1999) Nat Genet; [4] Horita, S., et al. (2014) J Am Soc Nephrol; [5] Parker, M. D., & Boron, W. F. (2013) Physiol Rev; [6] Parks, S. K., et al. (2013) Nat Rev Cancer; [7] Ch'en, I. Y., et al. (2008) J Physiol.

Other names

NBCe1NBC1KNBCpNBChhNBCSolute carrier family 4 member 4Sodium bicarbonate cotransporter 1

Inhibition of electrogenic sodium-bicarbonate cotransport to modulate intracellular and extracellular pH levels.