NMR resonance assignments and secondary structure of a mutant form of the human KCNE1 channel accessory protein that exhibits KCNE3-like function

  • Cheryl L. Law
  • Charles R. SandersEmail author


KCNQ1 (Q1) is a voltage-gated potassium channel that is modulated by members of the KCNE family, the best-characterized being KCNE1 (E1) and KCNE3 (E3). The Q1/E1 complex generates a channel with delayed activation and increased conductance. This complex is expressed in cardiomyocytes where it provides the IKs current that is critical for the repolarization phase of the cardiac action potential. The Q1/E3 complex, on the other hand, is expressed in epithelial cells of the colon and stomach, where it serves as a constitutively active leak channel to help maintain water and ion homeostasis. Studies show the single transmembrane segments (TMS) present in both E1 and E3 are essential to their distinct functions. More specifically, residues FTL located near the middle of the E1 TMS are essential for the delayed activation of Q1, while the corresponding TVG sites in E3 are critical for constitutive activation of the channel. Swapping these three residues leads to the switching of the functional properties for both Q1/E1FTL→TVG and Q1/E3TVG→FTL complexes. This work details the backbone assignments and chemical shifts for the E1FTL→TVG mutant, as determined using a suite of 3D NMR experiments along with specific and inverse amino acid isotopic labeling. The completed assignments can be used, in conjunction with other NMR experiments, to generate a 3D structure of E1FTL→TVG. The results of TALOS-N analysis of the chemical shifts are reported here. The E1FTL→TVG structure will be compared to the already available E1 and E3 structures to determine the roles that their TMS triplet motifs play in each protein to dictate their distinct channel-modulatory functions.


KCNQ1 Voltage-gated potassium channel KCNE1 KCNE3 Backbone resonance assignments Membrane protein NMR 



We thank Dr. Markus Voehler for help with setting up 3D NMR experiments and Dr. Keenan Taylor for assistance in processing NMR data.


This work was supported by NIH RO1 HL122010 and RO1 DC007416.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

These experiments comply with the current law of the country in which they were performed the USA.

Supplementary material

12104_2018_9867_MOESM1_ESM.pdf (266 kb)
Supplementary material 1 (PDF 266 KB)


  1. Abbott GW (2017) KCNE1 and KCNE3: the Yin and Yang of voltage-gated K+ channel regulation. Gene 576(1 pt 1):1–13. Google Scholar
  2. Barhanin J, Lesage F, Guillemare E, Fink M, Lazdunski M, Romey G (1996) K(V)LQT1 and lsK (minK) proteins associate to form the I(Ks) cardiac potassium current. Nature 384:78–80. ADSCrossRefGoogle Scholar
  3. Barro-Soria R, Ramentola R, Liina SI, Pereza ME, Kassb RS, Larssona PH (2017) KCNE1 and KCNE3 modulate KCNQ1 channels by affecting different gating transitions. Proc Natl Acad Sci USA 114(35):E7367–E7376. CrossRefGoogle Scholar
  4. Jespersen T, Grunnet M, Olesen SP (2005) The KCNQ1 potassium channel: from gene to physiological function. Physiology 20:408–416. CrossRefGoogle Scholar
  5. Kang C, Tian C, Sonnichens FD, Smith JA, Meiler J, George AL Jr, Vanoye CG, Kim HJ, Sanders CR (2008) Structure of KCNE1 and implications for how it modulates the KCNQ1 potassium channel. Biochem 47(31):7999–8006. CrossRefGoogle Scholar
  6. Kang C, Vanoye CG, Welch RC, Van Horn WD, Sanders CR (2010) Functional delivery of a membrane protein into oocyte membranes using bicelles. Biochemistry 49(4):653–655. CrossRefGoogle Scholar
  7. Kroncke BM, Van Horn WD, Smith JA, Kang C, Welch RC, Song Y, Nannermann DP, Taylor KC, Sisco NJ, George A Jr, Meiler J, Vanoye CG, Sanders CR (2016) Structural basis for KCNE3 modulation of potassium recycling in epithelia. Sci Adv 2:9. CrossRefGoogle Scholar
  8. McCrossan ZA, Abbott GW (2004) The MinK-related peptides. Neuropharmacology 47:787–821. CrossRefGoogle Scholar
  9. Melman Y, Domenech A, Luna S, McDonald TV (2000) Structural determinants of KvLQT1 control by the KCNE family of proteins. J Biol Chem 276(9):6439–6444. CrossRefGoogle Scholar
  10. Melman YF, Krumerman A, McDonald TV (2002) A single transmembrane site in the KCNE-encoded proteins controls the specificity of KvLQT1 channel gating. J Biol Chem 277:25187–25194. CrossRefGoogle Scholar
  11. Moseley HN, Sahota G, Montelione GT (2004) Assignement validation software suite for the evaluation and presentation of protein resonance assignment data. J Biomol NMR 28(4):341–355. CrossRefGoogle Scholar
  12. Organ-Darlin LE, Vermon AN, Giovanniello JR, Lu Y, Moshal K, Roder K, Li W, Koren G (2013) Interactions between hERG and KCNQ1 α-subunits are mediated by their COOH termini and modulated by cAMP. Am J Physiol Heart Circ Physiol 304(4):H589–H599. CrossRefGoogle Scholar
  13. Robbins J (2001) KCNQ potassium channels: physiology, pathophysiology, and pharmacology. Pharmacol Ther 90:1–19. CrossRefGoogle Scholar
  14. Schroeder BC, Waldegger S, Fehr S, Bleich M, Warth R, Greger R, Jentsch TJ (2000) A constitutively open potassium channel formed by KCNQ1 and KCNE3. Nature 403:196–199. ADSCrossRefGoogle Scholar
  15. Shen Y, Bax A (2013) Protein backbone and sidechain torsion angles predicted from NMR chemical shifts using artificial neural networks. J Biomol NMR 56:227–241. CrossRefGoogle Scholar
  16. Tian C, Vanoye CG, Kang C, Welch RC, Kim HJ, George AL, Sanders CR (2007) Preparation, functional characterization, and NMR studies of human KCNE1, a voltage-gated potassium channel accessory subunit associated with deafness and long QT syndrome. Biochemistry 46(41):11459–11472. CrossRefGoogle Scholar
  17. Wang B, Wang Y, Wishart DS (2010) A probabilistic approach for validating protein NMR chemical shift assignments. J Biomol NMR 47(2):85–99CrossRefGoogle Scholar

Copyright information

© Springer Nature B.V. 2019

Authors and Affiliations

  1. 1.Department of Biochemistry and Center for Structural BiologyVanderbilt University School of Medicine Basic SciencesNashvilleUSA

Personalised recommendations