Journal article
Two inwardly rectifying potassium channels, Irk1 and Irk2, play redundant roles in Drosophila renal tubule function
American journal of physiology. Regulatory, integrative and comparative physiology, Vol.309(7), pp.R747-R756
10/2015
DOI: 10.1152/ajpregu.00148.2015
PMCID: PMC4666928
PMID: 26224687
Abstract
Inwardly rectifying potassium channels play essential roles in renal physiology across phyla. Barium-sensitive K(+) conductances are found on the basolateral membrane of a variety of insect Malpighian (renal) tubules, including Drosophila melanogaster. We found that barium decreases the lumen-positive transepithelial potential difference in isolated perfused Drosophila tubules and decreases fluid secretion and transepithelial K(+) flux. In those insect species in which it has been studied, transcripts from multiple genes encoding inwardly rectifying K(+) channels are expressed in the renal (Malpighian) tubule. In Drosophila melanogaster, this includes transcripts of the Irk1, Irk2, and Irk3 genes. The role of each of these gene products in renal tubule function is unknown. We found that simultaneous knockdown of Irk1 and Irk2 in the principal cell of the fly tubule decreases transepithelial K(+) flux, with no additive effect of Irk3 knockdown, and decreases barium sensitivity of transepithelial K(+) flux by ∼50%. Knockdown of any of the three inwardly rectifying K(+) channels individually has no effect, nor does knocking down Irk3 simultaneously with Irk1 or Irk2. Irk1/Irk2 principal cell double-knockdown tubules remain sensitive to the kaliuretic effect of cAMP. Inhibition of the Na(+)/K(+)-ATPase with ouabain and Irk1/Irk2 double knockdown have additive effects on K(+) flux, and 75% of transepithelial K(+) transport is due to Irk1/Irk2 or ouabain-sensitive pathways. In conclusion, Irk1 and Irk2 play redundant roles in transepithelial ion transport in the Drosophila melanogaster renal tubule and are additive to Na(+)/K(+)-ATPase-dependent pathways.
Details
- Title: Subtitle
- Two inwardly rectifying potassium channels, Irk1 and Irk2, play redundant roles in Drosophila renal tubule function
- Creators
- Yipin Wu - Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas; andMichel Baum - Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas; and Department of Pediatrics, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, TexasChou-Long Huang - Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas; andAylin R Rodan - Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas; and aylin.rodan@utsouthwestern.edu
- Resource Type
- Journal article
- Publication Details
- American journal of physiology. Regulatory, integrative and comparative physiology, Vol.309(7), pp.R747-R756
- DOI
- 10.1152/ajpregu.00148.2015
- PMID
- 26224687
- PMCID
- PMC4666928
- NLM abbreviation
- Am J Physiol Regul Integr Comp Physiol
- ISSN
- 0363-6119
- eISSN
- 1522-1490
- Grant note
- DK079328 / NIDDK NIH HHS T32 DK007257 / NIDDK NIH HHS DK59530 / NIDDK NIH HHS P30 DK079328 / NIDDK NIH HHS K08 DK091316 / NIDDK NIH HHS DK078596 / NIDDK NIH HHS DK091316 / NIDDK NIH HHS DK41612 / NIDDK NIH HHS
- Language
- English
- Date published
- 10/2015
- Academic Unit
- Nephrology; Internal Medicine
- Record Identifier
- 9984094209802771
Metrics
30 Record Views