Na+/Ca2+ exchanger in Drosophila: Cloning, expression, and transport differences

Abdul Ruknudin, Carmen Valdivia, Paulo Kofuji, W. J. Lederer, Dan H. Schulze

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27 Scopus citations


cDNAs for the Na+/Ca2+ exchanger from Drosophila melanogaster (Dmel/Ncx) have been cloned by homology screening using the human heart Na+/Ca2+ exchanger cDNA. The overall deduced protein structure for Dme]/Ncx is similar to that of mammalian Na+/Ca2+ exchanger genes NCX1 and NCX2, having six hydrophobic regions in the amino terminus separated from six at the carboxy-terminal end by a large intracellular loop. Sequence comparison of the Drosophila exchanger cDNAs with NCX1 and NCX2 Na+/Ca2+ exchangers are ~46% identical at the deduced amino acid level. Consensus phosphorylation sites for both protein kinase C and protein kinase A are present on the intracellular loop region of the Dmel/Ncx. Alternative splicing for the Dmel/Ncx gene is suggested in the same intracellular loop region as demonstrated for NCX1. Functionally, the Drosophila Na+/Ca2+ exchanger expressed in oocytes differs from expressed mammalian NCX1 with regard to Ca2+ transport in Ca2+/Ca2+ exchange and the effect of monovalent-dependent Ca2+/Ca2+ exchange. The Dmel/Ncx gene maps to chromosome 3 (93A-B) using in situ hybridization to polytene chromosomes, the same position as the Na+-K+-ATPase, a related transporter. We conclude that, although extracellular Na+ concentration-dependent Ca2+ transport is subserved by both human and Drosophila Na+/Ca2+ exchangers, there are clear and important differences in the transporters, which should be useful in deducing how the Na+/Ca2+ exchanger protein function depends on its structure.

Original languageEnglish (US)
Pages (from-to)C257-C265
JournalAmerican Journal of Physiology - Cell Physiology
Issue number1 42-1
StatePublished - Jul 1997


  • Alternative splicing
  • Calcium
  • Drosophila melanogaster
  • Functional expression
  • Isotopic exchange
  • Sodium-calcium exchanger


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