Plasma membrane mechanical stress activates TRPC5 channels

PLoS One. 2015 Apr 7;10(4):e0122227. doi: 10.1371/journal.pone.0122227. eCollection 2015.

Abstract

Mechanical forces exerted on cells impose stress on the plasma membrane. Cells sense this stress and elicit a mechanoelectric transduction cascade that initiates compensatory mechanisms. Mechanosensitive ion channels in the plasma membrane are responsible for transducing the mechanical signals to electrical signals. However, the mechanisms underlying channel activation in response to mechanical stress remain incompletely understood. Transient Receptor Potential (TRP) channels serve essential functions in several sensory modalities. These channels can also participate in mechanotransduction by either being autonomously sensitive to mechanical perturbation or by coupling to other mechanosensory components of the cell. Here, we investigated the response of a TRP family member, TRPC5, to mechanical stress. Hypoosmolarity triggers Ca2+ influx and cationic conductance through TRPC5. Importantly, for the first time we were able to record the stretch-activated TRPC5 current at single-channel level. The activation threshold for TRPC5 was found to be 240 mOsm for hypoosmotic stress and between -20 and -40 mmHg for pressure applied to membrane patch. In addition, we found that disruption of actin filaments suppresses TRPC5 response to hypoosmotic stress and patch pipette pressure, but does not prevent the activation of TRPC5 by stretch-independent mechanisms, indicating that actin cytoskeleton is an essential transduction component that confers mechanosensitivity to TRPC5. In summary, our findings establish that TRPC5 can be activated at the single-channel level when mechanical stress on the cell reaches a certain threshold.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / drug effects
  • Animals
  • Antibodies / immunology
  • CHO Cells
  • Calcium / metabolism
  • Cell Membrane / metabolism*
  • Cricetinae
  • Cricetulus
  • Cytochalasin D / pharmacology
  • HEK293 Cells
  • Humans
  • Mechanotransduction, Cellular / physiology
  • Mice
  • Osmotic Pressure
  • Patch-Clamp Techniques
  • Stress, Mechanical*
  • TRPC Cation Channels / genetics
  • TRPC Cation Channels / immunology
  • TRPC Cation Channels / metabolism*

Substances

  • Antibodies
  • TRPC Cation Channels
  • Trpc5 protein, mouse
  • Cytochalasin D
  • Calcium

Grants and funding

This work was supported by CUHK478710, CUHK478011, T13-706/11, AoE/M-05/12 and CUHK2/CRF/11G from the Hong Kong RGC, Grant 81371284 from Natural Science Foundation of China, and Grant 1301043020 from the third installment of Anhui Provincial Science and Technology Plan 2013. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.