Cloning and characterization of a potassium-dependent sodium/calcium exchanger in Drosophila

• Published in: The Journal of cell biology Vol. 147; no. 3; pp. 659 - 669
• Main Authors: Haug-Ckollet, K, Pearson, B, Webel, R, Szerencsei, R.T, Winkfein, R.J, Schnetkamp, P.P.M, Colley, N.J
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 01.11.1999; The Rockefeller University Press
• Subjects: Amino Acid Sequence; amino acid sequences; Animals; Antiporters; Base Sequence; BASIC BIOLOGICAL SCIENCES; Body Patterning; brain; Calcium; Calcium Signaling; Carrier Proteins - antagonists & inhibitors; Carrier Proteins - chemistry; Carrier Proteins - genetics; Carrier Proteins - metabolism; cell biology; Cell Line; Cellular biology; central nervous system; Chromosomes - genetics; Cloning; Cloning, Molecular; Complementary DNA; compound eyes; development; Drosophila; Drosophila melanogaster; Drosophila melanogaster - embryology; Drosophila melanogaster - genetics; Drosophila melanogaster - growth & development; Drosophila melanogaster - metabolism; Drosophila Proteins; embryo (animal); embryogenesis; Embryos; Eye - cytology; Eye - embryology; Eye - growth & development; Eye - metabolism; genbank/af190455; gene expression; genes; Homeostasis; Imaginal discs; inorganic ions; Insects; ion transport; Larva - growth & development; Larva - metabolism; membrane proteins; messenger RNA; molecular conformation; Molecular Sequence Data; Monensin - pharmacology; Na@u+/Ca@@u2+@ exchanger; Nckx30C gene; Nervous System - cytology; Nervous System - embryology; Nervous System - growth & development; Nervous System - metabolism; Neurons; nucleotide sequences; Original; photoreceptor; Photoreceptor Cells, Invertebrate - embryology; Photoreceptor Cells, Invertebrate - growth & development; Photoreceptor Cells, Invertebrate - metabolism; Photoreceptors; plasma membrane; protein topology; Retinal rods; RNA, Messenger - analysis; RNA, Messenger - genetics; Sequence Alignment; Sequence Homology, Amino Acid; signal transduction; Sodium; Sodium-Calcium Exchanger; Temporal arteritis; ventral nerve cord; wingless (wg) gene; wingless gene
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.147.3.659

Sodium/calcium(-potassium) exchangers (NCX and NCKX) are critical for the rapid extrusion of calcium, which follows the stimulation of a variety of excitable cells. To further understand the mechanisms of calcium regulation in signaling, we have cloned a Drosophila sodium/calcium-potassium exchanger, Nckx30C. The overall deduced protein topology for NCKX30C is similar to that of mammalian NCKX, having five membrane-spanning domains in the NH2terminus separated from six at the COOH-terminal end by a large intracellular loop. We show that NCKX30C functions as a potassium-dependent sodium/calcium exchanger, and is not only expressed in adult neurons as was expected, but is also expressed during ventral nerve cord development in the embryo and in larval imaginal discs. Nckx30C is expressed in a dorsal-ventral pattern in the eye-antennal disc in a pattern that is similar to, but broader than that of wingless, suggesting that large fluxes of calcium may be occurring during imaginal disc development. Nckx30C may not only function in the removal of calcium and maintenance of calcium homeostasis during signaling in the adult, but may also play a critical role in signaling during development.