PDZ-domain interactions and apical expression of type IIa Na/Pi cotransporters
AUTOR(ES)
Hernando, Nati
FONTE
The National Academy of Sciences
RESUMO
Type IIa Na/Pi cotransporters are expressed in renal proximal brush border and are the major determinants of inorganic phosphate (Pi) reabsorption. Their carboxyl-terminal tail contains information for apical expression, and interacts by means of its three terminal amino acids with several PSD95/DglA/ZO-1-like domain (PDZ)-containing proteins. Two of these proteins, NaPi-Cap1 and Na/H exchanger-regulatory factor 1 (NHERF1), colocalize with the cotransporter in the proximal brush border. We used opossum kidney cells to test the hypothesis of a potential role of PDZ-interactions on the apical expression of the cotransporter. We found that opossum kidney cells contain NaPi-Cap1 and NHERF1 mRNAs. For NHERF1, an apical location of the protein could be documented; this location probably reflects interaction with the cytoskeleton by means of the MERM-binding domain. Overexpression of PDZ domains involved in interaction with the cotransporter (PDZ-1/NHERF1 and PDZ-3/NaPi-Cap1) had a dominant–negative effect, disturbing the apical expression of the cotransporter without affecting the actin cytoskeleton or the basolateral expression of Na/K-ATPase. These data suggest an involvement of PDZ-interactions on the apical expression of type IIa cotransporters.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=129376Documentos Relacionados
- Requirement of a leucine residue for (apical) membrane expression of type IIb NaPi cotransporters
- The Usher syndrome proteins cadherin 23 and harmonin form a complex by means of PDZ-domain interactions
- Expression cloning of human and rat renal cortex Na/Pi cotransport.
- Cloning and expression of cDNA for a Na/Pi cotransport system of kidney cortex.
- Bridge-1, a Novel PDZ-Domain Coactivator of E2A-Mediated Regulation of Insulin Gene Transcription