Cell Physiology

Localization of endogenous and recombinant Na+-driven anion exchanger protein NDAE1 fromDrosophila melanogaster

Christopher M. Sciortino, Lamara D. Shrode, Bonnie R. Fletcher, Peter J. Harte, Michael F. Romero


Na+-dependent Cl/HCO 3 exchange activity helps maintain intracellular pH (pHi) homeostasis in many invertebrate and vertebrate cell types. Our laboratory cloned and characterized a Na+-dependent Cl/HCO 3 exchanger (NDAE1) fromDrosophila melanogaster (Romero MF, Henry D, Nelson S, Harte PJ, and Sciortino CM. J Biol Chem 275: 24552–24559, 2000). In the present study we used immunohistochemical and Western blot techniques to characterize the developmental expression, subcellular localization, and tissue distribution of NDAE1 protein in D. melanogaster. We have shown that a polyclonal antibody raised against the NH2terminus of NDAE1 (αCWR57) recognizes NDAE1 electrophysiologically characterized in Xenopus oocytes. Moreover, our results begin to delineate the NDAE1 topology, i.e., both the NH2and COOH termini are intracellular. NDAE1 is expressed throughoutDrosophila development in the central and peripheral nervous systems, sensilla, and the alimentary tract (Malpighian tubules, gut, and salivary glands). Coimmunolabeling of larval tissues with NDAE1 antibody and a monoclonal antibody to the Na+-K+-ATPase α-subunit revealed that the majority of NDAE1 is located at the basolateral membranes of Malpighian tubule cells. These results suggest that NDAE1 may be a key pHi regulatory protein and may contribute to basolateral ion transport in epithelia and nervous system of Drosophila.

  • electrophysiology
  • fusion proteins
  • immunohistochemistry
  • development


  • This work was supported by an American Heart Association grant, a Howard Hughes Medical Institute Grant to Case Western Reserve University (M. F. Romero), and National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Grant DK-56218 (M. F. Romero). C. M. Sciortino was supported by an NIDDK Predoctoral Fellowship (DK-07678). L. D. Shrode was supported by a National Heart, Lung, and Blood Institute Postdoctoral Fellowship (HL-07415).

  • Address for reprint requests and other correspondence: M. F. Romero, Dept. of Physiology & Biophysics, Case Western Reserve Univ. School of Medicine, 2119 Abington Rd., Cleveland, OH 44106-4970 (E-mail: mfr2{at}po.cwru.edu).

  • The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

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