The Piezo2 ion channel is mechanically activated by low-threshold positive pressure

Sci Rep. 2019 Apr 23;9(1):6446. doi: 10.1038/s41598-019-42492-4.

Abstract

Recent parallel studies clearly indicated that Merkel cells and the mechanosensitive piezo2 ion channel play critical roles in the light-touch somatosensation. Moreover, piezo2 was suggested to be a light-touch sensing ion channel without a role in pain sensing in mammals. However, biophysical characteristics of piezo2, such as single channel conductance and sensitivities to various mechanical stimuli, are unclear, hampering a precise understanding of its role in touch sensation. Here, we describe the biophysical properties of piezo2 in human Merkel cell carcinoma (MCC)-13 cells; piezo2 is a low-threshold, positive pressure-specific, curvature-sensitive, mechanically activated cation channel with a single channel conductance of ~28.6 pS. Application of step indentations under the whole-cell mode of the patch-clamp technique, and positive pressures ≥5 mmHg under the cell-attached mode, activated piezo2 currents in MCC-13 and human embryonic kidney 293 T cells where piezo2 was overexpressed. By contrast, application of a negative pressure failed to activate piezo2 in these cells, whereas both positive and negative pressure activated piezo1 in a similar manner. Our results are the first to demonstrate single channel recordings of piezo2. We anticipate that our findings will be a starting point for a more sophisticated understanding of piezo2 roles in light-touch sensation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • HEK293 Cells
  • Humans
  • Ion Channels / metabolism*
  • Mechanotransduction, Cellular
  • Pressure*
  • Touch*

Substances

  • Ion Channels
  • PIEZO2 protein, human