Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
Renal brush border membrane sodium/phosphate (Na/Pi)-cotransport activity is inhibited by hormonal mechanisms involving activation of protein kinases A and C. The recently cloned rat renal Na/Pi-cotransporter (NaPi-2) contains several protein kinase C but no protein kinase A consensus sites [17, 20]. In the present study we have expressed wild type and polymutant (protein kinase C consensus sites removed) NaPi-2-transporters in Xenopus laevis oocytes. The expression of transport function as well as the basic transport properties were unaffected by the removal of the consensus sites. Pharmacological activation of protein kinase C with phorbol 12,13-didecanoate (PDD) led to a time-dependent inhibition of expressed wild type Na/Pi-cotransport function; simultaneous exposure to staurosporine (0.3) prevented the PDD induced (50 nM) inhibition. The kinase-C-mediated inhibition was not prevented by the removal of the protein kinase C consensus sites. Pharmacological activation of protein kinase A (dibutyryl adenosine 3':5':cyclic monophosphate (cAMP)/forskolin) had no effect on wild type NaPi-2-induced oocyte Na/Pi-cotransport. It is concluded that the protein-kinase-C-mediated regulation of expressed Na/Pi-cotransport does not involve the predicted consensus sites. The involvement of "cryptic" phosphorylation sites and/or of a phosphorylated "regulatory" protein is discussed.
Beguin,
Phosphorylation of the Na,K-ATPase alpha-subunit by protein kinase A and C in vitro and in intact cells. Identification of a novel motif for PKC-mediated phosphorylation.
1994, Pubmed,
Xenbase
Beguin,
Phosphorylation of the Na,K-ATPase alpha-subunit by protein kinase A and C in vitro and in intact cells. Identification of a novel motif for PKC-mediated phosphorylation.
1994,
Pubmed
,
Xenbase
Blumenthal,
Modulation by cAMP of a slowly activating potassium channel expressed in Xenopus oocytes.
1992,
Pubmed
,
Xenbase
Busch,
An amino acid mutation in a potassium channel that prevents inhibition by protein kinase C.
1992,
Pubmed
,
Xenbase
Busch,
Electrophysiological analysis of Na+/Pi cotransport mediated by a transporter cloned from rat kidney and expressed in Xenopus oocytes.
1994,
Pubmed
,
Xenbase
Busch,
Regulation by second messengers of the slowly activating, voltage-dependent potassium current expressed in Xenopus oocytes.
1992,
Pubmed
,
Xenbase
Chang,
Protein kinase A (PKA) still activates CFTR chloride channel after mutagenesis of all 10 PKA consensus phosphorylation sites.
1993,
Pubmed
Custer,
Expression of Na-P(i) cotransport in rat kidney: localization by RT-PCR and immunohistochemistry.
1994,
Pubmed
Dousa,
Effect of colchicine on urinary phosphate and regulation by parathyroid hormone.
1976,
Pubmed
Dunlay,
PTH receptor coupling to phospholipase C is an alternate pathway of signal transduction in bone and kidney.
1990,
Pubmed
Hammerman,
Phosphate transport across renal proximal tubular cell membranes.
1986,
Pubmed
Hayes,
Role of N-linked glycosylation in rat renal Na/Pi-cotransport.
1994,
Pubmed
,
Xenbase
Kempson,
Parathyroid hormone action on phosphate transporter mRNA and protein in rat renal proximal tubules.
1995,
Pubmed
Kempson,
Parathyroid hormone action on phosphate transport is inhibited by high osmolality.
1990,
Pubmed
Levi,
Cellular mechanisms of acute and chronic adaptation of rat renal P(i) transporter to alterations in dietary P(i).
1994,
Pubmed
Magagnin,
Expression cloning of human and rat renal cortex Na/Pi cotransport.
1993,
Pubmed
,
Xenbase
Murai,
Molecular cloning and sequence analysis of human genomic DNA encoding a novel membrane protein which exhibits a slowly activating potassium channel activity.
1989,
Pubmed
,
Xenbase
Murer,
Renal sodium-phosphate cotransport.
1994,
Pubmed
Murer,
Cellular mechanisms in proximal tubular reabsorption of inorganic phosphate.
1991,
Pubmed
,
Xenbase
Takumi,
Cloning of a membrane protein that induces a slow voltage-gated potassium current.
1988,
Pubmed
,
Xenbase
Vasilets,
Activation of protein kinase C by phorbol ester induces downregulation of the Na+/K(+)-ATPase in oocytes of Xenopus laevis.
1990,
Pubmed
,
Xenbase
Weinman,
CAMP-mediated inhibition of the renal brush border membrane Na+-H+ exchanger requires a dissociable phosphoprotein cofactor.
1993,
Pubmed
