Reaction: SLC34A1,2 cotransports Pi, 3Na+ from extracellular region to cytosol
- in pathway: Type II Na+/Pi cotransporters
SLC34A1 encodes Na+/Pi cotransporter (NaPi-IIa) which is expressed in the kidney in the renal proximal tubule (Magagnin et al. 1993). SLC34A2 encodes NaPi-IIb which is abundantly expressed in lung and to a lesser degree in tissues of epithelial origin including small intestine, pancreas, prostate, and kidney (Field et al. 1999). In the lung, SLC34A2 is expressed only in alveolar type II cells, which are responsible for surfactant production, so it is proposed that it uptakes liberated phosphate from the alveolar fluid for surfactant production. Both NaPi-IIa and NaPi-IIb cotransport inorganic phosphate (Pi) with three Na+ ions (electrogenic transport) (Forster et al. 1999, 2002).
Defects in SLC34A1 are the cause of hypophosphatemic nephrolithiasis/osteoporosis type 1 (NPHLOP1) (Prie et al. 2002). Defects in SLC34A2 are a cause of pulmonary alveolar microlithiasis, a rare disease characterised by the deposition of calcium phosphate microliths throughout the lung (Corut et al. 2006).
Defects in SLC34A1 are the cause of hypophosphatemic nephrolithiasis/osteoporosis type 1 (NPHLOP1) (Prie et al. 2002). Defects in SLC34A2 are a cause of pulmonary alveolar microlithiasis, a rare disease characterised by the deposition of calcium phosphate microliths throughout the lung (Corut et al. 2006).
Reaction - small molecule participants:
Pi [cytosol]
Na+ [cytosol]
Pi [extracellular region]
Na+ [extracellular region]
Pi [cytosol]
Na+ [cytosol]
Pi [extracellular region]
Na+ [extracellular region]
Reactome.org reaction link: R-HSA-427656
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Reaction input - small molecules:
hydrogenphosphate
sodium(1+)
hydrogenphosphate
sodium(1+)
Reaction output - small molecules:
hydrogenphosphate
sodium(1+)
hydrogenphosphate
sodium(1+)
Reactome.org link: R-HSA-427656