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Phosphate transporters and their function


Biber, Jürg; Hernando, Nati; Forster, Ian (2013). Phosphate transporters and their function. Annual Review of Physiology, 75:535-550.

Abstract

Plasma phosphate concentration is maintained within a relatively narrow range by control of renal reabsorption of filtered inorganic phosphate (P(i)). P(i) reabsorption is a transcellular process that occurs along the proximal tubule. P(i) flux at the apical (luminal) brush border membrane represents the rate-limiting step and is mediated by three Na(+)-dependent P(i) cotransporters (members of the SLC34 and SLC20 families). The putative proteins responsible for basolateral P(i) flux have not been identified. The transport mechanism of the two kidney-specific SLC34 proteins (NaPi-IIa and NaPi-IIc) and of the ubiquitously expressed SLC20 protein (PiT-2) has been studied by heterologous expression to reveal important differences in kinetics, stoichiometry, and substrate specificity. Studies on the regulation of the abundance of the respective proteins highlight significant differences in the temporal responses to various hormonal and nonhormonal factors that can influence P(i) homeostasis. The phenotypes of mice deficient in NaPi-IIa and NaPi-IIc indicate that NaPi-IIa is responsible for most P(i) renal reabsorption. In contrast, in the human kidney, NaPi-IIc appears to have a relatively greater role. The physiological relevance of PiT-2 to P(i) reabsorption remains to be elucidated.

Abstract

Plasma phosphate concentration is maintained within a relatively narrow range by control of renal reabsorption of filtered inorganic phosphate (P(i)). P(i) reabsorption is a transcellular process that occurs along the proximal tubule. P(i) flux at the apical (luminal) brush border membrane represents the rate-limiting step and is mediated by three Na(+)-dependent P(i) cotransporters (members of the SLC34 and SLC20 families). The putative proteins responsible for basolateral P(i) flux have not been identified. The transport mechanism of the two kidney-specific SLC34 proteins (NaPi-IIa and NaPi-IIc) and of the ubiquitously expressed SLC20 protein (PiT-2) has been studied by heterologous expression to reveal important differences in kinetics, stoichiometry, and substrate specificity. Studies on the regulation of the abundance of the respective proteins highlight significant differences in the temporal responses to various hormonal and nonhormonal factors that can influence P(i) homeostasis. The phenotypes of mice deficient in NaPi-IIa and NaPi-IIc indicate that NaPi-IIa is responsible for most P(i) renal reabsorption. In contrast, in the human kidney, NaPi-IIc appears to have a relatively greater role. The physiological relevance of PiT-2 to P(i) reabsorption remains to be elucidated.

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Additional indexing

Item Type:Journal Article, refereed, further contribution
Communities & Collections:04 Faculty of Medicine > Institute of Physiology
07 Faculty of Science > Institute of Physiology

04 Faculty of Medicine > Center for Integrative Human Physiology
Dewey Decimal Classification:570 Life sciences; biology
610 Medicine & health
Language:English
Date:2013
Deposited On:22 Mar 2013 14:05
Last Modified:05 Apr 2016 16:39
Publisher:Annual Reviews
ISSN:0066-4278
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1146/annurev-physiol-030212-183748
PubMed ID:23398154

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