title: Ca2+ regulation of ion transport in the Na+/Ca2+ exchanger.
abstract: The binding of Ca(2+) to two adjacent Ca(2+)-binding domains, CBD1 and CBD2, regulates ion transport in the Na(+)/Ca(2+) exchanger. As sensors for intracellular Ca(2+), the CBDs form electrostatic switches that induce the conformational changes required to initiate and sustain Na(+)/Ca(2+) exchange. Depending on the presence of a few key residues in the Ca(2+)-binding sites, zero to four Ca(2+) ions can bind with affinities between 0.1 to 20 μm. Importantly, variability in CBD2 as a consequence of alternative splicing modulates not only the number and affinities of the Ca(2+)-binding sites in CBD2 but also the Ca(2+) affinities in CBD1.
authors: Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University Basel, CH-4058 Basel, Switzerland. mark.hilge@unibas.ch.
authors: Mark
authors: M
authors: Hilge
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D002151:Calorimetry / Q000379:methods; D018360:Crystallography, X-Ray / Q000379:methods; D004331:Drosophila melanogaster; D006801:Humans; D007477:Ions; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D019831:Sodium-Calcium Exchanger / Q000737:chemistry*; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D007477:Ions; D019831:Sodium-Calcium Exchanger; D002118:Calcium