Skip to main content
PMC home page
Genetics logoLink to Genetics
. 2002 Feb;160(2):561–569. doi: 10.1093/genetics/160.2.561

The Drosophila inebriated-encoded neurotransmitter/osmolyte transporter: dual roles in the control of neuronal excitability and the osmotic stress response.

Xi Huang 1, Yanmei Huang 1, Raj Chinnappan 1, Claire Bocchini 1, Michael C Gustin 1, Michael Stern 1
PMCID: PMC1461969  PMID: 11861562

Abstract

Water reabsorption by organs such as the mammalian kidney and insect Malpighian tubule/hindgut requires a region of hypertonicity within the organ. To balance the high extracellular osmolarity, cells within these regions accumulate small organic molecules called osmolytes. These osmolytes can accumulate to a high level without toxic effects on cellular processes. Here we provide evidence consistent with the possibility that the two protein isoforms encoded by the inebriated (ine) gene, which are members of the Na+/Cl--dependent neurotransmitter/osmolyte transporter family, perform osmolyte transport within the Malpighian tubule and hindgut. We show that ine mutants lacking both isoforms are hypersensitive to osmotic stress, which we assayed by maintaining flies on media containing NaCl, KCl, or sorbitol, and that this hypersensitivity is completely rescued by high-level ectopic expression of the ine-RB isoform. We provide evidence that this hypersensitivity represents a role for ine that is distinct from the increased neuronal excitability phenotype of ine mutants. Finally, we show that each ine genotype exhibits a "threshold" [NaCl]: long-term maintenance on NaCl-containing media above, but not below, the threshold causes lethality. Furthermore, this threshold value increases with the amount of ine activity. These data suggest that ine mutations confer osmotic stress sensitivity by preventing osmolyte accumulation within the Malpighian tubule and hindgut.

Full Text

The Full Text of this article is available as a PDF (173.5 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Alonso J. M., Hirayama T., Roman G., Nourizadeh S., Ecker J. R. EIN2, a bifunctional transducer of ethylene and stress responses in Arabidopsis. Science. 1999 Jun 25;284(5423):2148–2152. doi: 10.1126/science.284.5423.2148. [DOI] [PubMed] [Google Scholar]
  2. Amara S. G., Kuhar M. J. Neurotransmitter transporters: recent progress. Annu Rev Neurosci. 1993;16:73–93. doi: 10.1146/annurev.ne.16.030193.000445. [DOI] [PubMed] [Google Scholar]
  3. Borden L. A., Smith K. E., Gustafson E. L., Branchek T. A., Weinshank R. L. Cloning and expression of a betaine/GABA transporter from human brain. J Neurochem. 1995 Mar;64(3):977–984. doi: 10.1046/j.1471-4159.1995.64030977.x. [DOI] [PubMed] [Google Scholar]
  4. Borden L. A., Smith K. E., Hartig P. R., Branchek T. A., Weinshank R. L. Molecular heterogeneity of the gamma-aminobutyric acid (GABA) transport system. Cloning of two novel high affinity GABA transporters from rat brain. J Biol Chem. 1992 Oct 15;267(29):21098–21104. [PubMed] [Google Scholar]
  5. Brand A. H., Dormand E. L. The GAL4 system as a tool for unravelling the mysteries of the Drosophila nervous system. Curr Opin Neurobiol. 1995 Oct;5(5):572–578. doi: 10.1016/0959-4388(95)80061-1. [DOI] [PubMed] [Google Scholar]
  6. Brand A. H., Perrimon N. Targeted gene expression as a means of altering cell fates and generating dominant phenotypes. Development. 1993 Jun;118(2):401–415. doi: 10.1242/dev.118.2.401. [DOI] [PubMed] [Google Scholar]
  7. Brewster J. L., de Valoir T., Dwyer N. D., Winter E., Gustin M. C. An osmosensing signal transduction pathway in yeast. Science. 1993 Mar 19;259(5102):1760–1763. doi: 10.1126/science.7681220. [DOI] [PubMed] [Google Scholar]
  8. Chiu C., Ross L. S., Cohen B. N., Lester H. A., Gill S. S. The transporter-like protein inebriated mediates hyperosmotic stimuli through intracellular signaling. J Exp Biol. 2000 Dec;203(Pt 23):3531–3546. doi: 10.1242/jeb.203.23.3531. [DOI] [PubMed] [Google Scholar]
  9. Ferraris J. D., Williams C. K., Martin B. M., Burg M. B., García-Pérez A. Cloning, genomic organization, and osmotic response of the aldose reductase gene. Proc Natl Acad Sci U S A. 1994 Oct 25;91(22):10742–10746. doi: 10.1073/pnas.91.22.10742. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Ganetzky B., Wu C. F. Neurogenetic analysis of potassium currents in Drosophila: synergistic effects on neuromuscular transmission in double mutants. J Neurogenet. 1983 Sep;1(1):17–28. doi: 10.3109/01677068309107069. [DOI] [PubMed] [Google Scholar]
  11. Garcia-Perez A., Burg M. B. Renal medullary organic osmolytes. Physiol Rev. 1991 Oct;71(4):1081–1115. doi: 10.1152/physrev.1991.71.4.1081. [DOI] [PubMed] [Google Scholar]
  12. Garrett-Engele P., Moilanen B., Cyert M. S. Calcineurin, the Ca2+/calmodulin-dependent protein phosphatase, is essential in yeast mutants with cell integrity defects and in mutants that lack a functional vacuolar H(+)-ATPase. Mol Cell Biol. 1995 Aug;15(8):4103–4114. doi: 10.1128/mcb.15.8.4103. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Jan Y. N., Jan L. Y., Dennis M. J. Two mutations of synaptic transmission in Drosophila. Proc R Soc Lond B Biol Sci. 1977 Jul 28;198(1130):87–108. doi: 10.1098/rspb.1977.0087. [DOI] [PubMed] [Google Scholar]
  14. Liu Y. H., Huang F., Fei J., Zhao J. X., Gu Q. B., Schwarz W., Guo L. H. Val 70, Phe 72 and the last seven amino acid residues of C-terminal are essential to the function of norepinephrine transporter. Cell Res. 1998 Dec;8(4):311–315. doi: 10.1038/cr.1998.31. [DOI] [PubMed] [Google Scholar]
  15. Mabjeesh N. J., Kanner B. I. Neither amino nor carboxyl termini are required for function of the sodium- and chloride-coupled gamma-aminobutyric acid transporter from rat brain. J Biol Chem. 1992 Feb 5;267(4):2563–2568. [PubMed] [Google Scholar]
  16. Meikle A. J., Reed R. H., Gadd G. M. Osmotic adjustment and the accumulation of organic solutes in whole cells and protoplasts of Saccharomyces cerevisiae. J Gen Microbiol. 1988 Nov;134(11):3049–3060. doi: 10.1099/00221287-134-11-3049. [DOI] [PubMed] [Google Scholar]
  17. Rasola A., Galietta L. J., Barone V., Romeo G., Bagnasco S. Molecular cloning and functional characterization of a GABA/betaine transporter from human kidney. FEBS Lett. 1995 Oct 16;373(3):229–233. doi: 10.1016/0014-5793(95)01052-g. [DOI] [PubMed] [Google Scholar]
  18. Sheikh-Hamad D., Di Mari J., Suki W. N., Safirstein R., Watts B. A., 3rd, Rouse D. p38 kinase activity is essential for osmotic induction of mRNAs for HSP70 and transporter for organic solute betaine in Madin-Darby canine kidney cells. J Biol Chem. 1998 Jan 16;273(3):1832–1837. doi: 10.1074/jbc.273.3.1832. [DOI] [PubMed] [Google Scholar]
  19. Smardo F. L., Jr, Burg M. B., Garcia-Perez A. Kidney aldose reductase gene transcription is osmotically regulated. Am J Physiol. 1992 Mar;262(3 Pt 1):C776–C782. doi: 10.1152/ajpcell.1992.262.3.C776. [DOI] [PubMed] [Google Scholar]
  20. Soehnge H., Huang X., Becker M., Whitley P., Conover D., Stern M. A neurotransmitter transporter encoded by the Drosophila inebriated gene. Proc Natl Acad Sci U S A. 1996 Nov 12;93(23):13262–13267. doi: 10.1073/pnas.93.23.13262. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Stern M., Ganetzky B. Identification and characterization of inebriated, a gene affecting neuronal excitability in Drosophila. J Neurogenet. 1992 Sep;8(3):157–172. doi: 10.3109/01677069209083445. [DOI] [PubMed] [Google Scholar]
  22. Stern M., Kreber R., Ganetzky B. Dosage effects of a Drosophila sodium channel gene on behavior and axonal excitability. Genetics. 1990 Jan;124(1):133–143. doi: 10.1093/genetics/124.1.133. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Uchida S., Yamauchi A., Preston A. S., Kwon H. M., Handler J. S. Medium tonicity regulates expression of the Na(+)- and Cl(-)-dependent betaine transporter in Madin-Darby canine kidney cells by increasing transcription of the transporter gene. J Clin Invest. 1993 Apr;91(4):1604–1607. doi: 10.1172/JCI116367. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Wu C. F., Wong F. Frequency characteristics in the visual system of Drosophila: genetic dissection of electroretinogram components. J Gen Physiol. 1977 Jun;69(6):705–724. doi: 10.1085/jgp.69.6.705. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Yager J., Richards S., Hekmat-Scafe D. S., Hurd D. D., Sundaresan V., Caprette D. R., Saxton W. M., Carlson J. R., Stern M. Control of Drosophila perineurial glial growth by interacting neurotransmitter-mediated signaling pathways. Proc Natl Acad Sci U S A. 2001 Aug 21;98(18):10445–10450. doi: 10.1073/pnas.191107698. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Yamauchi A., Uchida S., Preston A. S., Kwon H. M., Handler J. S. Hypertonicity stimulates transcription of gene for Na(+)-myo-inositol cotransporter in MDCK cells. Am J Physiol. 1993 Jan;264(1 Pt 2):F20–F23. doi: 10.1152/ajprenal.1993.264.1.F20. [DOI] [PubMed] [Google Scholar]
  27. Yancey P. H., Clark M. E., Hand S. C., Bowlus R. D., Somero G. N. Living with water stress: evolution of osmolyte systems. Science. 1982 Sep 24;217(4566):1214–1222. doi: 10.1126/science.7112124. [DOI] [PubMed] [Google Scholar]

Articles from Genetics are provided here courtesy of Oxford University Press

RESOURCES