Journal of Membrane Biology

, 227:141

Mechanical Force and Cytoplasmic Ca2+ Activate Yeast TRPY1 in Parallel

  • Zhenwei Su
  • Xinliang Zhou
  • Stephen H. Loukin
  • Yoshiro Saimi
  • Ching Kung


The ability to sense mechanical and osmotic stimuli is vital to all organisms from mammals to bacteria. Members of the transient receptor potential (TRP) ion-channel family have attracted intense attention for their involvement in mechanosensation. The yeast homologue TRPY1 can clearly be activated by hypertonic shock in vivo and by stretch force under patch clamp. Like its animal counterparts, TRPY1 is polymodal, being gated by membrane stretch force and by cytoplasmic Ca2+. Here, we investigated how these two gating principles interact. We found that stretch force can induce some channel activation without cytoplasmic Ca2+. Tens of micromolar Ca2+ greatly enhance the observed force-induced activities, with open probabilities following well the Boltzmann distribution, in which the two gating energies are summed as exponents. To map this formalism to structures, we found Ca2+-binding proteins such as calmodulin or calcineurin to be unnecessary. However, removing a dense cluster of negative charges in the C-terminal cytoplasmic domain of TRPY1 greatly diminishes the Ca2+ activation as well as its influence on force activation. We also found a strategic point upstream of this charge cluster, at which insertion of amino acids weakens Ca2+ activation considerably but leaves the mechanosensitivity nearly intact. These results led to a structure–function model in which Ca2+ binding to the cytoplasmic domain and stretching of the membrane-embedded domain both generate gating force, reaching the gate in parallel.


Ion channel TRP channel Mechanosensitive channel Yeast channel Stretch force activation Ca2+ activation 


  1. Bandell M, Dubin AE, Petrus MJ, Orth A, Mathur J, Hwang SW, Patapoutian A (2006) High-throughput random mutagenesis screen reveals TRPM8 residues specifically required for activation by menthol. Nat Neurosci 9:493–500PubMedCrossRefGoogle Scholar
  2. Batiza AF, Schulz T, Masson PH (1996) Yeast respond to hypotonic shock with a calcium pulse. J Biol Chem 271:23357–23362PubMedCrossRefGoogle Scholar
  3. Bertl A, Slayman CL (1990) Cation-selective channels in the vacuolar membrane of Saccharomyces: dependence on calcium, redox state, and voltage. Proc Natl Acad Sci USA 87:7824–7828PubMedCrossRefGoogle Scholar
  4. Christensen AP, Corey DP (2007) TRP channels in mechanosensation: direct or indirect activation? Nat Rev Neurosci 8:510–521PubMedCrossRefGoogle Scholar
  5. Cox DH, Cui J, Aldrich RW (1997) Allosteric gating of a large conductance Ca-activated K+ channel. J Gen Physiol 110:257–281PubMedCrossRefGoogle Scholar
  6. Denis V, Cyert MS (2002) Internal Ca2+ release in yeast is triggered by hypertonic shock and mediated by a TRP channel homologue. J Cell Biol 156:29–34PubMedCrossRefGoogle Scholar
  7. Doerner JF, Gisselmann G, Hatt H, Wetzel CH (2007) Transient receptor potential channel A1 is directly gated by calcium ions. J Biol Chem 282:13180–13189PubMedCrossRefGoogle Scholar
  8. Geiser JR, van Tuinen D, Brockerhoff SE, Neff MM, Davis TN (1991) Can calmodulin function without binding calcium? Cell 65:949–959PubMedCrossRefGoogle Scholar
  9. Grandl J, Hu H, Bandell M, Bursulaya B, Schmidt M, Petrus M, Patapoutian A (2008) Pore region of TRPV3 ion channel is specifically required for heat activation. Nat Neurosci 11:1007–1013PubMedCrossRefGoogle Scholar
  10. Ho SN, Hunt HD, Horton RM, Pullen JK, Pease LR (1989) Site-directed mutagenesis by overlap extension using the polymerase chain reaction. Gene 77:51–59PubMedCrossRefGoogle Scholar
  11. Hofmann T, Chubanov V, Gudermann T, Montell C (2003) TRPM5 is a voltage-modulated and Ca2+-activated monovalent selective cation channel. Curr Biol 13:1153–1158PubMedCrossRefGoogle Scholar
  12. Honore E (2007) The neuronal background K2P channels: focus on TREK1. Nat Rev Neurosci 8:251–261PubMedCrossRefGoogle Scholar
  13. Horrigan FT, Aldrich RW (2002) Coupling between voltage sensor activation, Ca2+ binding and channel opening in large conductance (BK) potassium channels. J Gen Physiol 120:267–305PubMedCrossRefGoogle Scholar
  14. Hurst AC, Petrov E, Kloda A, Nguyen T, Hool L, Martinac B (2008) MscS, the bacterial mechanosensitive channel of small conductance. Int J Biochem Cell Biol 40:581–585PubMedCrossRefGoogle Scholar
  15. Jiang Y, Lee A, Chen J, Cadene M, Chait BT, MacKinnon R (2002) Crystal structure and mechanism of a calcium-gated potassium channel. Nature 417:515–522PubMedCrossRefGoogle Scholar
  16. Kung C (2005) A possible unifying principle for mechanosensation. Nature 436:647–654PubMedCrossRefGoogle Scholar
  17. Latorre R, Brauchi S (2006) Large conductance Ca2+-activated K+ (BK) channel: activation by Ca2+ and voltage. Biol Res 39:385–401PubMedCrossRefGoogle Scholar
  18. Launay P, Fleig A, Perraud AL, Scharenberg AM, Penner R, Kinet JP (2002) TRPM4 is a Ca2+-activated nonselective cation channel mediating cell membrane depolarization. Cell 109:397–407PubMedCrossRefGoogle Scholar
  19. Loukin S, Zhou X, Kung C, Saimi Y (2008) A genome-wide survey suggests an osmoprotective role for vacuolar Ca2+ release in cell wall-compromised yeast. FASEB J 22:2405–2415PubMedCrossRefGoogle Scholar
  20. Magleby KL (2003) Gating mechanism of BK (Slo1) channels: so near, yet so far. J Gen Physiol 121:81–96PubMedCrossRefGoogle Scholar
  21. Martinac B, Saimi Y, Kung C (2008) Ion channels in microbes. Physiol Rev 88:1449–1490PubMedCrossRefGoogle Scholar
  22. McHugh D, Flemming R, Xu SZ, Perraud AL, Beech DJ (2003) Critical intracellular Ca2+ dependence of transient receptor potential melastatin 2 (TRPM2) cation channel activation. J Biol Chem 278:11002–11006PubMedCrossRefGoogle Scholar
  23. Moiseenkova-Bell VY, Stanciu LA, Serysheva II, Tobe BJ, Wensel TG (2008) Structure of TRPV1 channel revealed by electron cryomicroscopy. Proc Natl Acad Sci USA 105:7451–7455PubMedCrossRefGoogle Scholar
  24. Nilius B, Vriens J, Prenen J, Droogmans G, Voets T (2004) TRPV4 calcium entry channel: a paradigm for gating diversity. Am J Physiol 286:C195–C205CrossRefGoogle Scholar
  25. Nilius B, Prenen J, Tang J, Wang C, Owsianik G, Janssens A, Voets T, Zhu MX (2005) Regulation of the Ca2+ sensitivity of the nonselective cation channel TRPM4. J Biol Chem 280:6423–6433PubMedCrossRefGoogle Scholar
  26. Niu X, Qian X, Magleby KL (2004) Linker-gating ring complex as passive spring and Ca2+-dependent machine for a voltage- and Ca2+-activated potassium channel. Neuron 42:745–756PubMedCrossRefGoogle Scholar
  27. Palmer CP, Zhou XL, Lin J, Loukin SH, Kung C, Saimi Y (2001) A TRP homolog in Saccharomyces cerevisiae forms an intracellular Ca2+-permeable channel in the yeast vacuolar membrane. Proc Natl Acad Sci USA 98:7801–7805PubMedCrossRefGoogle Scholar
  28. Pedersen SF, Owsianik G, Nilius B (2005) TRP channels: an overview. Cell Calcium 38:233–252PubMedCrossRefGoogle Scholar
  29. Ramsey IS, Delling M, Clapham DE (2006) An introduction to TRP channels. Annu Rev Physiol 68:619–647PubMedCrossRefGoogle Scholar
  30. Saimi Y, Kung C (2002) Calmodulin as an ion channel subunit. Annu Rev Physiol 64:289–311PubMedCrossRefGoogle Scholar
  31. Su Z, Zhou X, Haynes WJ, Loukin SH, Anishkin A, Saimi Y, Kung C (2007) Yeast gain-of-function mutations reveal structure–function relationships conserved among different subfamilies of transient receptor potential channels. Proc Natl Acad Sci USA 104:19607–19612PubMedCrossRefGoogle Scholar
  32. Venkatachalam K, Montell C (2007) TRP channels. Annu Rev Biochem 76:387–417PubMedCrossRefGoogle Scholar
  33. Voets T, Droogmans G, Wissenbach U, Janssens A, Flockerzi V, Nilius B (2004) The principle of temperature-dependent gating in cold- and heat-sensitive TRP channels. Nature 430:748–754PubMedCrossRefGoogle Scholar
  34. Wada Y, Ohsumi Y, Tanifuji M, Kasai M, Anraku Y (1987) Vacuolar ion channel of the yeast, Saccharomyces cerevisiae. J Biol Chem 262:17260–17263PubMedGoogle Scholar
  35. Wang YY, Chang RB, Waters HN, McKemy DD, Liman ER (2008) The nociceptor ion channel TRPA1 is potentiated and inactivated by permeating calcium ions. J Biol Chem 283:32691–32703PubMedCrossRefGoogle Scholar
  36. Zhou X, Su Z, Anishkin A, Haynes WJ, Friske EM, Loukin SH, Kung C, Saimi Y (2007) Yeast screens show aromatic residues at the end of the sixth helix anchor transient receptor potential channel gate. Proc Natl Acad Sci USA 104:15555–15559PubMedCrossRefGoogle Scholar
  37. Zhou XL, Batiza AF, Loukin SH, Palmer CP, Kung C, Saimi Y (2003) The transient receptor potential channel on the yeast vacuole is mechanosensitive. Proc Natl Acad Sci USA 100:7105–7110PubMedCrossRefGoogle Scholar
  38. Zurborg S, Yurgionas B, Jira JA, Caspani O, Heppenstall PA (2007) Direct activation of the ion channel TRPA1 by Ca2+. Nat Neurosci 10:277–279PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Zhenwei Su
    • 1
  • Xinliang Zhou
    • 1
  • Stephen H. Loukin
    • 1
  • Yoshiro Saimi
    • 1
  • Ching Kung
    • 1
    • 2
  1. 1.Laboratory of Molecular BiologyUniversity of Wisconsin–MadisonMadisonUSA
  2. 2.Department of GeneticsUniversity of Wisconsin–MadisonMadisonUSA

Personalised recommendations