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Amino acids involved in sodium interaction of murine type II Na(+)-P(i) cotransporters expressed in Xenopus oocytes.
de La Horra C, Hernando N, Forster I, Biber J, Murer H.
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Type IIa and IIb Na+-Pi cotransporters are highly conserved proteins expressed in brush border membranes of proximal tubules and small intestine, respectively. The kinetics of IIa and IIb differ significantly: type IIb is saturated at lower concentrations of Na+ and Pi. To define the domain responsible for the difference in Na+ affinity we constructed several mouse IIa-IIb chimeras as well as site-directed mutagenized cotransporters. Pi uptake activity was determined after injection of cRNAs into Xenopus laevis oocytes. From the chimera experiments we concluded that the domain containing part of the second intracellular loop, the fifth transmembrane domain (TD) and part of the third extracellular loop determines the specific Na+ activation properties for both types of cotransporter. Within this domain only a few residues located in the fifth TD are not conserved between type IIa and IIb. Site-directed mutagenesis on non-conserved residues was performed. Substitution of F402 of IIa by the corresponding L418 from IIb yielded a cotransporter that behaved like the IIb. On the other hand, substitution of the specific L418 of IIb by the corresponding F402 of IIa produced a cotransporter with a Na+ activation similar to IIa. (Single letter amino acid nomenclature is used throughout the paper.) These data suggest that the specific Na+ activation properties exhibited by type IIa and type IIb Na+-Pi cotransporters are at least in part due to the presence of a specific amino acid (F402 in IIa, and L418 in IIb) within the fifth TD of the protein.
Amstutz,
Effect of pH on phosphate transport in rat renal brush border membrane vesicles.
1985, Pubmed
Amstutz,
Effect of pH on phosphate transport in rat renal brush border membrane vesicles.
1985,
Pubmed Beck,
Targeted inactivation of Npt2 in mice leads to severe renal phosphate wasting, hypercalciuria, and skeletal abnormalities.
1998,
Pubmed Béliveau,
Electrogenicity of phosphate transport by renal brush-border membranes.
1988,
Pubmed Busch,
Electrophysiological analysis of Na+/Pi cotransport mediated by a transporter cloned from rat kidney and expressed in Xenopus oocytes.
1994,
Pubmed
,
Xenbase Cheng,
Sodium gradient-dependent phosphate transport in renal brush border membrane vesicles.
1981,
Pubmed Cross,
Mechanism and regulation of intestinal phosphate absorption.
1990,
Pubmed Custer,
Expression of Na-P(i) cotransport in rat kidney: localization by RT-PCR and immunohistochemistry.
1994,
Pubmed de la Horra,
Molecular determinants of pH sensitivity of the type IIa Na/P(i) cotransporter.
2000,
Pubmed
,
Xenbase Di Cera,
The Na+ binding site of thrombin.
1995,
Pubmed Forster,
Stoichiometry and Na+ binding cooperativity of rat and flounder renal type II Na+-Pi cotransporters.
1999,
Pubmed
,
Xenbase Forster,
The voltage dependence of a cloned mammalian renal type II Na+/Pi cotransporter (NaPi-2).
1998,
Pubmed
,
Xenbase Gmaj,
Cellular mechanisms of inorganic phosphate transport in kidney.
1986,
Pubmed Guinto,
Critical role of W60d in thrombin allostery.
1997,
Pubmed Hartmann,
Transport characteristics of a murine renal Na/Pi-cotransporter.
1995,
Pubmed
,
Xenbase Hayes,
Role of N-linked glycosylation in rat renal Na/Pi-cotransport.
1994,
Pubmed
,
Xenbase Hilfiker,
Characterization of a murine type II sodium-phosphate cotransporter expressed in mammalian small intestine.
1998,
Pubmed
,
Xenbase Kaim,
Molecular basis for the coupling ion selectivity of F1F0 ATP synthases: probing the liganding groups for Na+ and Li+ in the c subunit of the ATP synthase from Propionigenium modestum.
1997,
Pubmed Lambert,
Properties of the mutant Ser-460-Cys implicate this site in a functionally important region of the type IIa Na(+)/P(i) cotransporter protein.
1999,
Pubmed
,
Xenbase Lambert,
Studies on the topology of the renal type II NaPi-cotransporter.
1999,
Pubmed
,
Xenbase Magagnin,
Expression cloning of human and rat renal cortex Na/Pi cotransport.
1993,
Pubmed
,
Xenbase Mense,
Residues of the fourth transmembrane segments of the Na,K-ATPase and the gastric H,K-ATPase contribute to cation selectivity.
2000,
Pubmed
,
Xenbase Murer,
A molecular view of proximal tubular inorganic phosphate (Pi) reabsorption and of its regulation.
1997,
Pubmed Murer,
Membrane permeability. Epithelial transport proteins: physiology and pathophysiology.
1998,
Pubmed Murer,
Molecular mechanisms of renal apical Na/phosphate cotransport.
1996,
Pubmed Murer,
Homer Smith Award. Cellular mechanisms in proximal tubular Pi reabsorption: some answers and more questions.
1992,
Pubmed Nakagawa,
Transport of phosphate by plasma membranes of the jejunum and kidney of the mouse model of hypophosphatemic vitamin D-resistant rickets.
1993,
Pubmed Oberbauer,
In vivo suppression of the renal Na+/Pi cotransporter by antisense oligonucleotides.
1996,
Pubmed Pourcher,
Melibiose permease of Escherichia coli: mutation of aspartic acid 55 in putative helix II abolishes activation of sugar binding by Na+ ions.
1991,
Pubmed Sorribas,
Cloning of a Na/Pi cotransporter from opossum kidney cells.
1994,
Pubmed
,
Xenbase Traebert,
Expression of type II Na-P(i) cotransporter in alveolar type II cells.
1999,
Pubmed Verri,
Cloning of a rabbit renal Na-Pi cotransporter, which is regulated by dietary phosphate.
1995,
Pubmed
,
Xenbase Werner,
Expression of renal transport systems for inorganic phosphate and sulfate in Xenopus laevis oocytes.
1990,
Pubmed
,
Xenbase
