| http://purl.uniprot.org/citations/17164249 | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | http://purl.uniprot.org/core/Journal_Citation |
| http://purl.uniprot.org/citations/17164249 | http://www.w3.org/2000/01/rdf-schema#comment | "The SLC24 gene family Na+/Ca2+-K+ exchangers (NCKX) are bidirectional plasma membrane transporters whose main function is the extrusion of Ca2+ from the cytosol. In this study, we used human embryonic kidney 293 cells expressing human retinal cone/brain NCKX2 to examine its Na+ affinity and kinetic parameters of Ca2+ transport. With the use of the ionophore gramicidin to control alkali cation concentrations across the plasma membrane, application of high intracellular Na+ promoted large NCKX2-mediated increases in intracellular free Ca2+ in the 15-20 microm range; this also resulted in inactivation of NCKX2 transport, the first description of this novel kinetic state. The affinity of NCKX2 for internal Na+ was found to be sigmoidal, with a Hill coefficient of 2.6 and Kd = 50 mm. The time-dependent (t(1/2) approximately 40s) inactivation of NCKX2 required high intracellular Na+ levels (Kd > 50 mm) as well as high occupancy of the extracellular Ca2+-binding site. Also reported are two residues whose substitution resulted in an increase in internal Na+ affinity to values of approximately 19 mm; these mutants also displayed enhanced inactivation, suggesting that inactivation requires binding of Na+ to its intracellular transport sites. These findings are the first report of a regulatory kinetic state of Ca2+ transport via NCKX2 Na+/Ca2+-K+ exchangers that may play a prominent role in regulation of Ca2+ extrusion in cellular environments such as neuronal synapses that experience frequent and dynamic Ca2+ fluxes."xsd:string |
| http://purl.uniprot.org/citations/17164249 | http://purl.org/dc/terms/identifier | "doi:10.1074/jbc.m609285200"xsd:string |
| http://purl.uniprot.org/citations/17164249 | http://purl.uniprot.org/core/author | "Altimimi H.F."xsd:string |
| http://purl.uniprot.org/citations/17164249 | http://purl.uniprot.org/core/author | "Schnetkamp P.P."xsd:string |
| http://purl.uniprot.org/citations/17164249 | http://purl.uniprot.org/core/date | "2007"xsd:gYear |
| http://purl.uniprot.org/citations/17164249 | http://purl.uniprot.org/core/name | "J Biol Chem"xsd:string |
| http://purl.uniprot.org/citations/17164249 | http://purl.uniprot.org/core/pages | "3720-3729"xsd:string |
| http://purl.uniprot.org/citations/17164249 | http://purl.uniprot.org/core/title | "Na+-dependent inactivation of the retinal cone/brain Na+/Ca2+-K+ exchanger NCKX2."xsd:string |
| http://purl.uniprot.org/citations/17164249 | http://purl.uniprot.org/core/volume | "282"xsd:string |
| http://purl.uniprot.org/citations/17164249 | http://www.w3.org/2004/02/skos/core#exactMatch | http://purl.uniprot.org/pubmed/17164249 |
| http://purl.uniprot.org/citations/17164249 | http://xmlns.com/foaf/0.1/primaryTopicOf | https://pubmed.ncbi.nlm.nih.gov/17164249 |
| http://purl.uniprot.org/uniprot/#_Q9UI40-mappedCitation-17164249 | http://www.w3.org/1999/02/22-rdf-syntax-ns#object | http://purl.uniprot.org/citations/17164249 |
| http://purl.uniprot.org/uniprot/Q9UI40 | http://purl.uniprot.org/core/mappedCitation | http://purl.uniprot.org/citations/17164249 |