Regulation of Na/Pi transporter in the proximal tubule.
The physiological tuning and pathophysiological alterations of renal proximal reabsorption of inorganic phosphate can be ascribed to the net amount of the Na/Pi-cotransporter NaPi-IIa localized in the brush border membrane. The net amount of NaPi-IIa appears to be the result of an endocytotic rate regulated by a complex network of different protein kinases. New approaches demonstrated that NaPi-IIa is part of heteromeric protein complexes, organized by PDZ (postsynaptic protein PSD95, Drosophila junction protein Disc-large, tight junction protein ZO-1) proteins. Such complexes are thought to play important roles in the apical positioning and regulated endocytosis of NaPi-IIa and therefore such interactions have to be considered when explaining proximal phosphate ion reabsorption.
Murer
Heini
H
Institute of Physiology, University Zürich, 8057 Switzerland. hmurer@access.unizh.ch
Hernando
Nati
N
Forster
Ian
I
Biber
Jürg
J
D000818:Animals; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D050608:Sodium-Phosphate Cotransporter Proteins; D050613:Sodium-Phosphate Cotransporter Proteins, Type IIa; D027981:Symporters / Q000737:chemistry / Q000378:metabolism*
D010710:Phosphates; C493554:SLC34A1 protein, human; D050608:Sodium-Phosphate Cotransporter Proteins; D050613:Sodium-Phosphate Cotransporter Proteins, Type IIa; D027981:Symporters; D012964:Sodium