|Name:||solute carrier family 8 (sodium-calcium exchanger), member 2|
|PubMed (8021246):|| Li Z, Matsuoka S, Hryshko LV, Nicoll DA, Bersohn MM, Burke EP, Lifton RP,Philipson KD. Cloning of the NCX2 isoform of the plasma membrane Na(+)-Ca2+ exchanger.J Biol Chem. 1994 Jul 1;269(26):17434-9. PMID: 8021246 [PubMed - indexed for MEDLINE]|
The Na(+)-Ca2+ exchanger is an important regulator of cellular Ca2+ levels, and one isoform of this transporter, NCX1, has been cloned previously (Nicoll, D.A., Longoni, S., and Philipson, K.D. (1990) Science 250, 562-565). We now report the cloning of a second isoform (NCX2) of the Na(+)-Ca2+ exchanger which was present in a rat brain cDNA library. NCX2 is predicted to code for a protein of 921 amino acids. NCX1 and NCX2 are 61 and 65% identical at the nucleotide and amino acid levels, respectively, and are the products of different genes. The genes for NCX1 and NCX2 are located on human chromosomes 2 and 14, respectively. Hydropathy profiles of the two exchangers are very similar. Transcripts of NCX2 are detected in brain and skeletal muscle. NCX2 was expressed in Xenopus oocytes and Na(+)-Ca2+ exchange activity was analyzed electrophysiologically by the giant inside-out, excised patch technique. Outward currents were evoked by the application of Na+ with the exchanger operating in the reversed mode (extracellular Ca2+ exchanging for intracellular Na+). The affinity for Na+ (30 mM) and the current-voltage relationship of NCX2 are similar to those for NCX1. Like NCX1, NCX2 is secondarily regulated by intracellular Ca2+, but the affinity of NCX2 for regulatory Ca2+ (1.5 microM) upon initial application of Na+ is lower than that of NCX1 (0.3 microM). The existence of multiple Na(+)-Ca2+ exchanger isoforms may provide flexibility for regulation and expression.
>sp|Q9UPR5|NAC2_HUMAN Sodium/calcium exchanger 2 OS=Homo sapiens GN=SLC8A2 PE=2 SV=2 MAPLALVGVTLLLAAPPCSGAATPTPSLPPPPANDSDTSTGGCQGSYRCQPGVLLPVWEPDDPSLGDKAARAVVYFVAMV YMFLGVSIIADRFMAAIEVITSKEKEITITKANGETSVGTVRIWNETVSNLTLMALGSSAPEILLSVIEVCGHNFQAGEL GPGTIVGSAAFNMFVVIAVCIYVIPAGESRKIKHLRVFFVTASWSIFAYVWLYLILAVFSPGVVQVWEALLTLVFFPVCV VFAWMADKRLLFYKYVYKRYRTDPRSGIIIGAEGDPPKSIELDGTFVGAEAPGELGGLGPGPAEARELDASRREVIQILK DLKQKHPDKDLEQLVGIANYYALLHQQKSRAFYRIQATRLMTGAGNVLRRHAADASRRAAPAEGAGEDEDDGASRIFFEP SLYHCLENCGSVLLSVTCQGGEGNSTFYVDYRTEDGSAKAGSDYEYSEGTLVFKPGETQKELRIGIIDDDIFEEDEHFFV RLLNLRVGDAQGMFEPDGGGRPKGRLVAPLLATVTILDDDHAGIFSFQDRLLHVSECMGTVDVRVVRSSGARGTVRLPYR TVDGTARGGGVHYEDACGELEFGDDETMKTLQVKIVDDEEYEKKDNFFIELGQPQWLKRGISALLLNQGDGDRKLTAEEE EARRIAEMGKPVLGENCRLEVIIEESYDFKNTVDKLIKKTNLALVIGTHSWREQFLEAITVSAGDEEEEEDGSREERLPS CFDYVMHFLTVFWKVLFACVPPTEYCHGWACFGVSILVIGLLTALIGDLASHFGCTVGLKDSVNAVVFVALGTSIPDTFA SKVAALQDQCADASIGNVTGSNAVNVFLGLGVAWSVAAVYWAVQGRPFEVRTGTLAFSVTLFTVFAFVGIAVLLYRRRPH IGGELGGPRGPKLATTALFLGLWLLYILFASLEAYCHIRGF