Functional Roles of Electrogenic Sodium Bicarbonate Cotransporter NBCe1 in Ocular Tissues

Masashi Suzuki, George Seki*, Hideomi Yamada, Shoko Horita , Toshiro Fujita
Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan

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© Suzuki et al.; Licensee Bentham Open.

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* Address correspondence to this author at the Department of Internal Medicine, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo 113-0033, Japan; Tel: +81-3-3815-5411, Ext. 33004; Fax: +81-3-5800-8806; E-mail:


Electrogenic Na+-HCO3- cotransporter NBCe1 is expressed in several tissues such as kidney, eye, and brain, where it may mediate distinct biological processes. In particular, NBCe1 in renal proximal tubules is essential for the regulation of systemic acid/base balance. On the other hand, NBCe1 in eye may be indispensable for the maintenance of tissue homeostasis. Consistent with this view, homozygous mutations in NBCe1 cause severe proximal renal tubular acidosis associated with ocular abnormalities such as band keratopathy, glaucoma, and cataract. The widespread expression of NBCe1 in eye suggests that the inactivation of NBCe1 per se may be responsible for the occurrence of these ocular abnormalities. In this review, we discuss about physiological and pathological roles of NBCe1 in eye.

Keywords: NBCe1, proximal renal tubular acidosis, band keratopathy, glaucoma, cataract.