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Calx, A Sodium-Calcium Exchanger of Drosophila melanogaster


Schwarz, Erich Marquard (1996) Calx, A Sodium-Calcium Exchanger of Drosophila melanogaster. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/M2PR-WT51.


Calcium extrusion is necessary for cellular survival and suspected to modulate cellular activity. Drosophila phototransduction is a promising system in which to study calcium export, since it is dominated by calcium activity yet, unlike most calcium-dependent signalling pathways, genetically pliable. The multiple roles of calcium flux in Drosophila phototransduction are reviewed in Chapter One.

Calx, a Drosophila ortholog of mammalian 3Na+/1Ca2+ exchangers, was isolated and characterized (Chapter Two). Calx's gene product has ~50% identity to its direct mammalian homologs, with more distant similarities to an exchanger-related superfamily. There exist at least seven alternately spliced adult Calx transcripts, with an alternatively spliced miniexon in Calx's protein-coding region. A full-length Calx cDNA of 5408 bp has lengthy, elaborate 5' and 3' UTRs. Calx transcripts are ubiquitously expressed in embryos and adult heads, with one 5.7 kb transcript expressed in photoreceptors; Calx protein is also ubiquitous in adult heads, with a notable presence in photoreceptors and neuropil. Heterologous expression of Calx in Xenopus oocytes shows that it encodes a bona fide sodium-calcium exchanger; unlike mammalian retinal exchangers, it does not depend on potassium for activity. Calx encodes two novel protein motifs, Calx-α and Calx-β. Both are intragenically duplicated, but they probably have different functions: Calx-α is likely to encode residues central to calcium export, while Calx-β may mediate intracellular signalling or cytoskeletal anchoring.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Calx, Na-Ca exchanger, sodium-calcium exchanger, Drosophila melanogaster
Degree Grantor:California Institute of Technology
Major Option:Molecular Biology
Minor Option:Biochemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Benzer, Seymour
Thesis Committee:
  • Benzer, Seymour (chair)
  • Anderson, David J.
  • Meyerowitz, Elliot M.
  • Simon, Melvin I.
  • Sternberg, Paul W.
Defense Date:21 August 1995
Non-Caltech Author Email:ems394 (AT)
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Record Number:CaltechTHESIS:10292019-132931068
Persistent URL:
Schwarz, Erich Marquard0000-0003-3151-4381
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11872
Deposited By: Mel Ray
Deposited On:29 Oct 2019 20:46
Last Modified:21 Dec 2019 03:05

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