A new study published in the journal Cell Reports reveals that a protein called Piezo 1 is directly responsible for sensing touch. Knowledge about Piezo 1 could be relevant for designing better pain medications and exploring future therapies for blood disorders, hypertension and more.
Piezo proteins transduce physical forces and are activated by mechanical indentation and stretching of cell membranes. By reconstituting these channels in lipid bilayers, Syeda et al show that Piezo 1 channels are stimulated in the absence of other cellular components via a variety of methods, including osmotic imbalance and membrane perturbation. Image credit: Syeda et al, doi: 10.1016/j.celrep.2016.10.033.
Piezo 1 is a so-called ‘ion channel,’ or gateway through the cell membrane.
When it senses mechanical force, it opens to allow ions to pass into the cell, starting a chain of events that send a signal to the brain — in other words, Piezo proteins control the sensation of touch.
“Out of all our senses, the sense of touch is the least understood, so significant efforts are being made to acquire a more complete understanding. We are only now unraveling the physiological roles of Piezo proteins,” said lead author Dr. Ruhma Syeda, a postdoctoral fellow at the Scripps Research Institute.
The current study addressed a lingering question about Piezo 1: does it sense touch directly, or is it influenced by nearby proteins and other cellular components?
To study this, Dr. Syeda and co-authors used a ‘reductionist’ approach.
In this system, researchers extract a protein from its native environment in the cell and study it in a simpler membrane environment. This enables them to see how the protein behaves on its own, without influence from other cellular players.
The authors found that Piezo 1 does appear to directly sense force by detecting tension in the cell membrane.
“It seems like it has a built-in sensor,” Dr. Syeda said.
The next step in this research is to better understand the molecular structure of Piezo 1 — which could lead to a ‘map’ of the protein and further insights into its function.
“I’m also very excited that this reductionist approach can be applied to other channels,” Dr. Syeda said.
“We’ll be able to understand more channels and proteins and their physiological roles.”
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Ruhma Syeda et al. 2016. Piezo 1 Channels Are Inherently Mechanosensitive. Cell Reports 17 (7): 1739-1746; doi: 10.1016/j.celrep.2016.10.033
