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???
Two maneuvers known to stimulate electrogenic sodium bicarbonate cotransporter 1 (NBCe1) activity are 1) deletion from the cytosolic amino-terminus (Nt) of NBCe1-C of an 87-amino acid sequence that contains an autoinhibitory domain (AID); and 2) binding of the protein IRBIT to elements within the same 87-amino acid module in a different variant, NBCe1-B. Helpful to understanding the relationship between these two phenomena would be an appreciation of the relative magnitude of stimulation caused by each maneuver for the same NBCe1 variant. In the present study, we performed two-electrode voltage-clamp on Xenopus oocytes expressing human NBCe1-B constructs, with and without human IRBIT constructs. We find that removal of the AID stimulates NBCe1-B to the same extent as coexpression of wild-type IRBIT. The potency of wild-type IRBIT apparently is reduced by the action of endogenous oocyte protein phosphatases: a mutant IRBIT that cannot be influenced by the action of protein phosphatase-1 stimulates NBCe1-B to an extent 50% greater than can be achieved by removal of the NBCe1-B AID. Thus the stimulatory effect of IRBIT cannot be explained solely by masking of autoinhibitory determinants within the AID. Finally, we find that an NBCe1-B construct that lacks amino acid residues 2-16 of the Nt is fully autoinhibited, but cannot be stimulated by IRBIT, indicating that autoinhibitory and IRBIT-binding determinants within the cytosolic Nt are not identical.
Ando,
IRBIT, a novel inositol 1,4,5-trisphosphate (IP3) receptor-binding protein, is released from the IP3 receptor upon IP3 binding to the receptor.
2003, Pubmed
Ando,
IRBIT, a novel inositol 1,4,5-trisphosphate (IP3) receptor-binding protein, is released from the IP3 receptor upon IP3 binding to the receptor.
2003,
Pubmed
Bevensee,
An electrogenic Na(+)-HCO(-)(3) cotransporter (NBC) with a novel COOH-terminus, cloned from rat brain.
2000,
Pubmed
,
Xenbase
Boron,
Modular structure of sodium-coupled bicarbonate transporters.
2009,
Pubmed
Boron,
Intracellular pH regulation in the renal proximal tubule of the salamander. Basolateral HCO3- transport.
1983,
Pubmed
Burnham,
Cloning and functional expression of a human kidney Na+:HCO3- cotransporter.
1997,
Pubmed
Choi,
Role of glycosylation in the renal electrogenic Na+-HCO3- cotransporter (NBCe1).
2003,
Pubmed
,
Xenbase
Choi,
Cloning and characterization of a human electrogenic Na+-HCO-3 cotransporter isoform (hhNBC).
1999,
Pubmed
,
Xenbase
Devogelaere,
Protein phosphatase-1 is a novel regulator of the interaction between IRBIT and the inositol 1,4,5-trisphosphate receptor.
2007,
Pubmed
Gagnon,
Volume sensitivity of cation-Cl- cotransporters is modulated by the interaction of two kinases: Ste20-related proline-alanine-rich kinase and WNK4.
2006,
Pubmed
,
Xenbase
He,
IRBIT, inositol 1,4,5-triphosphate (IP3) receptor-binding protein released with IP3, binds Na+/H+ exchanger NHE3 and activates NHE3 activity in response to calcium.
2008,
Pubmed
Heyer,
Stoichiometry of the rat kidney Na+-HCO3- cotransporter expressed in Xenopus laevis oocytes.
1999,
Pubmed
,
Xenbase
Liu,
Cloning and identification of two novel NBCe1 splice variants from mouse reproductive tract tissues: a comparative study of NCBT genes.
2011,
Pubmed
Lu,
Reversible and irreversible interactions of DIDS with the human electrogenic Na/HCO3 cotransporter NBCe1-A: role of lysines in the KKMIK motif of TM5.
2007,
Pubmed
,
Xenbase
McAlear,
Electrogenic Na/HCO3 cotransporter (NBCe1) variants expressed in Xenopus oocytes: functional comparison and roles of the amino and carboxy termini.
2006,
Pubmed
,
Xenbase
Musa-Aziz,
Using fluorometry and ion-sensitive microelectrodes to study the functional expression of heterologously-expressed ion channels and transporters in Xenopus oocytes.
2010,
Pubmed
,
Xenbase
Parker,
Characterization of human SLC4A10 as an electroneutral Na/HCO3 cotransporter (NBCn2) with Cl- self-exchange activity.
2008,
Pubmed
,
Xenbase
Romero,
Cloning and functional expression of rNBC, an electrogenic Na(+)-HCO3- cotransporter from rat kidney.
1998,
Pubmed
,
Xenbase
Romero,
Expression cloning and characterization of a renal electrogenic Na+/HCO3- cotransporter.
1997,
Pubmed
,
Xenbase
Sciortino,
Cation and voltage dependence of rat kidney electrogenic Na(+)-HCO(-)(3) cotransporter, rkNBC, expressed in oocytes.
1999,
Pubmed
,
Xenbase
Shirakabe,
IRBIT, an inositol 1,4,5-trisphosphate receptor-binding protein, specifically binds to and activates pancreas-type Na+/HCO3- cotransporter 1 (pNBC1).
2006,
Pubmed
,
Xenbase
Toye,
The human NBCe1-A mutant R881C, associated with proximal renal tubular acidosis, retains function but is mistargeted in polarized renal epithelia.
2006,
Pubmed
,
Xenbase
Wakula,
Degeneracy and function of the ubiquitous RVXF motif that mediates binding to protein phosphatase-1.
2003,
Pubmed
Yang,
WNK1 and WNK4 modulate CFTR activity.
2007,
Pubmed
,
Xenbase
Yang,
IRBIT coordinates epithelial fluid and HCO3- secretion by stimulating the transporters pNBC1 and CFTR in the murine pancreatic duct.
2009,
Pubmed
Yang,
WNK kinases regulate thiazide-sensitive Na-Cl cotransport.
2003,
Pubmed
,
Xenbase
Yang,
IRBIT governs epithelial secretion in mice by antagonizing the WNK/SPAK kinase pathway.
2011,
Pubmed
