Piezo channels

Thibaud Parpaite (1) , Bertrand Coste (1)

1 CRN2M - Centre de recherche en neurobiologie - neurophysiologie de Marseille

What are Piezo proteins? Piezo proteins constitute the first family of excitatory ion channels gated by mechanical forces described in vertebrates. These ion channels are involved in cell mechanotransduction, the conversion of mechanical forces into biological signals. Is mechanotransduction important? Yes it is! All living organisms are subjected to mechanical forces from their environment and rely on mechanotransduction for their survival. For instance, our senses of touch, mechanical pain, proprioception, hearing and balance depend on mechanically-activated channels. And besides sensory systems, mechanotransduction is involved in diverse physiological functions including vascular tone and blood flow regulation, bone and muscle homeostasis, flow sensing in kidney and respiratory systems. Does mechanotransduction rely exclusively on mechanosensitive channels? No, it does not. Cells integrate a variety of mechanical stimuli such as shear stress, tension, torsion and compression and translate them into short term effects (i.e. changes in ion concentrations and voltage) and long term effects via changes in gene expression. Many membrane-associated molecules are involved in mechanotransduction including ion channels, specialized cytoskeletal proteins, cell junction molecules, G-protein-coupled receptors and kinases. The specificity of mechanosensitive ion channels is to convert mechanical forces into electrical signal within tens of microseconds. This is particularly suited for fast signaling that occurs into specialized sensory cells involved in touch and hearing. So, why is Piezo discovery valuable for mammalian physiology? Although some mechanically-activated ion channels have been characterized decades ago in bacteria and invertebrate species, these channels are either not conserved in vertebrates or have lost their mechanotransduction properties during evolution towards higher species. Therefore, the molecular identification of mammalian mechanotransduction channels has remained a long-standing question in the field of sensory functions. The discovery of Piezo proteins in 2010 has fueled mechanotransduction-related research, opening the field for prolific work in a wide range of research area over the past few years. What is known about Piezo genes? There is no piezo gene in bacteria, but Piezo homologues are found in plants and animals including protozoa. Most vertebrates have two copies of Piezo genes, Piezo1 and 2, encoding relatively large proteins of over 2 500 and 2 800 amino acids in human, respectively. These genes are expressed in a wide range of tissues in mammals, highlighting potential contribution of Piezo channels to mechanotransduction in various organs.

Mots clés: Proteins; Ion channel; Vertebrates; Mechanotransduction; Piezo

Domaines: Neurosciences

Thibaud Parpaite, Bertrand Coste. Piezo channels. Current Biology - CB, 2017, 27 (7), pp.R250-R252. ⟨10.1016/j.cub.2017.01.048⟩. ⟨hal-01765081⟩