Advertisement

Pflügers Archiv - European Journal of Physiology

, Volume 466, Issue 8, pp 1559–1570 | Cite as

A splice variant of the two-pore domain potassium channel TREK-1 with only one pore domain reduces the surface expression of full-length TREK-1 channels

  • Susanne Rinné
  • Vijay Renigunta
  • Günter Schlichthörl
  • Marylou Zuzarte
  • Stefan Bittner
  • Sven G. Meuth
  • Niels Decher
  • Jürgen Daut
  • Regina Preisig-Müller
Ion channels, receptors and transporters

Abstract

We have identified a novel splice variant of the human and rat two-pore domain potassium (K2P) channel TREK-1. The splice variant TREK-1e results from skipping of exon 5, which causes a frame shift in exon 6. The frame shift produces a novel C-terminal amino acid sequence and a premature termination of translation, which leads to a loss of transmembrane domains M3 and M4 and of the second pore domain. RT-PCR experiments revealed a preferential expression of TREK-1e in kidney, adrenal gland, and amygdala. TREK-1e was nonfunctional when expressed in Xenopus oocytes. However, both the surface expression and the current density of full-length TREK-1 were reduced by co-expression of TREK-1e. Live cell imaging in COS-7 cells transfected with GFP-tagged TREK-1e showed that this splice variant was retained in the endoplasmic reticulum (ER). Attachment of the C-terminus of TREK-1e to two different reporter proteins (Kir2.1 and CD8) led to a strong reduction in the surface expression of these fusion proteins. Progressive truncation of the C-terminus of TREK-1e in these reporter constructs revealed a critical region (amino acids 198 to 205) responsible for the intracellular retention. Mutagenesis experiments indicated that amino acids I204 and W205 are key residues mediating the ER retention of TREK-1e. Our results suggest that the TREK-1e splice variant may interfere with the vesicular traffic of full-length TREK-1 channels from the ER to the plasma membrane. Thus, TREK-1e might modulate the copy number of functional TREK-1 channels at the cell surface, providing a novel mechanism for fine tuning of TREK-1 currents.

Keywords

Alternative splicing K2P channel Potassium channels Splice variant TREK-1 

Notes

Acknowledgments

This work was supported by grants of the Deutsche Forschungsgemeinschaft SFB 593, TP A4 to J.D. and 1482-3/2 to N.D., the P.E. Kempkes Foundation (to S.R. and R.P.M.), and the Anneliese Pohl Stiftung to S.R.. We thank Caroline Rolfes and Thorsten Steinfeldt for the isolation of porcine adrenal gland. We are grateful to Andrea Schubert for excellent technical support.

Conflict of interest

The authors declare no conflict of interest.

References

  1. 1.
    Bittner S, Ruck T, Schuhmann MK, Herrmann AM, Maati HM, Bobak N, Gobel K, Langhauser F, Stegner D, Ehling P, Borsotto M, Pape HC, Nieswandt B, Kleinschnitz C, Heurteaux C, Galla HJ, Budde T, Wiendl H, Meuth SG (2013) Endothelial TWIK-related potassium channel-1 (TREK1) regulates immune-cell trafficking into the CNS. Nat Med 19:1161–1165. doi: 10.1038/nm.3303 PubMedCrossRefGoogle Scholar
  2. 2.
    Bockenhauer D, Zilberberg N, Goldstein SA (2001) KCNK2: reversible conversion of a hippocampal potassium leak into a voltage-dependent channel. Nat Neurosci 4:486–491. doi: 10.1038/87434 PubMedGoogle Scholar
  3. 3.
    Brohawn SG, del Marmol J, MacKinnon R (2012) Crystal structure of the human K2P TRAAK, a lipid- and mechano-sensitive K+ ion channel. Science 335:436–441. doi: 10.1126/science.1213808 PubMedCentralPubMedCrossRefGoogle Scholar
  4. 4.
    Fink M, Duprat F, Lesage F, Reyes R, Romey G, Heurteaux C, Lazdunski M (1996) Cloning, functional expression and brain localization of a novel unconventional outward rectifier K+ channel. EMBO J 15:6854–6862, PMID: 9003761PubMedCentralPubMedGoogle Scholar
  5. 5.
    Franks NP, Honore E (2004) The TREK K2P channels and their role in general anaesthesia and neuroprotection. Trends Pharmacol Sci 25:601–608. doi: 10.1016/j.tips.2004.09.003 PubMedCrossRefGoogle Scholar
  6. 6.
    Gu W, Schlichthörl G, Hirsch JR, Engels H, Karschin C, Karschin A, Derst C, Steinlein OK, Daut J (2002) Expression pattern and functional characteristics of two novel splice variants of the two-pore-domain potassium channel TREK-2. J Physiol 539:657–668. doi: 10.1113/jphysiol.2001.013432 PubMedCentralPubMedCrossRefGoogle Scholar
  7. 7.
    Han J, Kang D, Kim D (2003) Functional properties of four splice variants of a human pancreatic tandem-pore K+ channel, TALK-1. Am J Physiol Cell Physiol 285:C529–C538. doi: 10.1152/ajpcell.00601.2002 PubMedCrossRefGoogle Scholar
  8. 8.
    Kim D (2005) Physiology and pharmacology of two-pore domain potassium channels. Curr Pharm Des 11:2717–2736. doi: 10.2174/1381612054546824 PubMedCrossRefGoogle Scholar
  9. 9.
    Kim Y, Bang H, Kim D (1999) TBAK-1 and TASK-1, two-pore K+ channel subunits: kinetic properties and expression in rat heart. Am J Physiol 277:H1669–H1678, PMID: 10564119PubMedGoogle Scholar
  10. 10.
    Ma D, Nakata T, Zhang G, Hoshi T, Li M, Shikano S (2007) Differential trafficking of carboxyl isoforms of Ca2+-gated (Slo1) potassium channels. FEBS Lett 581:1000–1008. doi: 10.1016/j.febslet.2007.01.077 PubMedCentralPubMedCrossRefGoogle Scholar
  11. 11.
    Ma D, Zerangue N, Lin YF, Collins A, Yu M, Jan YN, Jan LY (2001) Role of ER export signals in controlling surface potassium channel numbers. Science 291:316–319. doi: 10.1126/science.291.5502.316 PubMedCrossRefGoogle Scholar
  12. 12.
    Miller AN, Long SB (2012) Crystal structure of the human two-pore domain potassium channel K2P1. Science 335:432–436. doi: 10.1126/science.1213274 PubMedCrossRefGoogle Scholar
  13. 13.
    Ozaita A, Vega-Saenz de Miera E (2002) Cloning of two transcripts, HKT4.1a and HKT4.1b, from the human two-pore K+ channel gene KCNK4. Chromosomal localization, tissue distribution and functional expression. Brain Res Mol Brain Res 102:18–27PubMedCrossRefGoogle Scholar
  14. 14.
    Patel AJ, Maingret F, Magnone V, Fosset M, Lazdunski M, Honore E (2000) TWIK-2, an inactivating 2P domain K+ channel. J Biol Chem 275:28722–28730. doi: 10.1074/jbc.M003755200 PubMedCrossRefGoogle Scholar
  15. 15.
    Renigunta V, Yuan H, Zuzarte M, Rinné S, Koch A, Wischmeyer E, Schlichthörl G, Gao Y, Karschin A, Jacob R, Schwappach B, Daut J, Preisig-Müller R (2006) The retention factor p11 confers an endoplasmic reticulum-localization signal to the potassium channel TASK-1. Traffic 7:168–181. doi: 10.1111/j.1600-0854.2005.00375.x PubMedCrossRefGoogle Scholar
  16. 16.
    Schutze MP, Peterson PA, Jackson MR (1994) An N-terminal double-arginine motif maintains type II membrane proteins in the endoplasmic reticulum. EMBO J 13:1696–1705PubMedCentralPubMedGoogle Scholar
  17. 17.
    Simkin D, Cavanaugh EJ, Kim D (2008) Control of the single channel conductance of K2P10.1 (TREK-2) by the amino-terminus: role of alternative translation initiation. J Physiol 586:5651–5663. doi: 10.1113/jphysiol.2008.161927 PubMedCentralPubMedCrossRefGoogle Scholar
  18. 18.
    Staudacher K, Baldea I, Kisselbach J, Staudacher I, Rahm AK, Schweizer PA, Becker R, Katus HA, Thomas D (2011) Alternative splicing determines mRNA translation initiation and function of human K2P10.1 K+ channels. J Physiol 589:3709–3720. doi: 10.1113/jphysiol.2011.210666 PubMedCentralPubMedGoogle Scholar
  19. 19.
    Thomas D, Plant LD, Wilkens CM, McCrossan ZA, Goldstein SA (2008) Alternative translation initiation in rat brain yields K2P2.1 potassium channels permeable to sodium. Neuron 58:859–870. doi: 10.1016/j.neuron.2008.04.016 PubMedCentralPubMedCrossRefGoogle Scholar
  20. 20.
    Veale EL, Rees KA, Mathie A, Trapp S (2010) Dominant negative effects of a non-conducting TREK1 splice variant expressed in brain. J Biol Chem 285:29295–29304. doi: 10.1074/jbc.M110.108423 PubMedCentralPubMedCrossRefGoogle Scholar
  21. 21.
    Wu YY, Singer CA, Buxton IL (2012) Variants of stretch-activated two-pore potassium channel TREK-1 associated with preterm labor in humans. Biol Reprod 87:96. doi: 10.1095/biolreprod.112.099499 PubMedCentralPubMedCrossRefGoogle Scholar
  22. 22.
    Xian Tao L, Dyachenko V, Zuzarte M, Putzke C, Preisig-Müller R, Isenberg G, Daut J (2006) The stretch-activated potassium channel TREK-1 in rat cardiac ventricular muscle. Cardiovasc Res 69:86–97. doi: 10.1016/j.cardiores.2005.08.018 CrossRefGoogle Scholar
  23. 23.
    Zerangue N, Schwappach B, Jan YN, Jan LY (1999) A new ER trafficking signal regulates the subunit stoichiometry of plasma membrane KATP channels. Neuron 22:537–548PubMedCrossRefGoogle Scholar
  24. 24.
    Zerangue N, Malan MJ, Fried SR, Dazin PF, Jan YN, Jan LY, Schwappach B (2001) Analysis of endoplasmic reticulum trafficking signals by combinatorial screening in mammalian cells. Proc Natl Acad Sci U S A 98:2431–2436. doi: 10.1073/pnas.05163019898/5/2431 PubMedCentralPubMedCrossRefGoogle Scholar
  25. 25.
    Zuzarte M, Rinné S, Schlichthörl G, Schubert A, Daut J, Preisig-Müller R (2007) A di-acidic sequence motif enhances the surface expression of the potassium channel TASK-3. Traffic 8:1093–1100. doi: 10.1111/j.1600-0854.2007.00593.x PubMedCrossRefGoogle Scholar
  26. 26.
    Zuzarte M, Heusser K, Renigunta V, Schlichthörl G, Rinné S, Wischmeyer E, Daut J, Schwappach B, Preisig-Müller R (2009) Intracellular traffic of the K+ channels TASK-1 and TASK-3: role of N- and C-terminal sorting signals and interaction with 14-3-3 proteins. J Physiol 587:929–952. doi: 10.1113/jphysiol.2008.164756 PubMedCentralPubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Susanne Rinné
    • 1
    • 2
    • 4
  • Vijay Renigunta
    • 1
  • Günter Schlichthörl
    • 1
  • Marylou Zuzarte
    • 1
  • Stefan Bittner
    • 3
  • Sven G. Meuth
    • 3
  • Niels Decher
    • 2
  • Jürgen Daut
    • 1
  • Regina Preisig-Müller
    • 1
    • 4
  1. 1.Institute for Physiology and Pathophysiology, Cell PhysiologyUniversity of MarburgMarburgGermany
  2. 2.Institute for Physiology and Pathophysiology, Vegetative PhysiologyUniversity of MarburgMarburgGermany
  3. 3.Department of NeurologyUniversity of MünsterMünsterGermany
  4. 4.Institute for Physiology and PathophysiologyPhilipps-University of MarburgMarburgGermany

Personalised recommendations