Scientists reveal how Venus fly trap plants snap shut
The mechanosensitive ion channel is related to channels found in variety
of other organisms

Date:
February 17, 2022
Source:
Scripps Research Institute
Summary:
Scientists have revealed the three-dimensional structure of
Flycatcher1, an aptly named protein channel that may enable Venus
fly trap plants to snap shut in response to prey. The structure
of Flycatcher1 helps shed light on longstanding questions about
the remarkably sensitive touch response of Venus fly traps. The
structure also gives the researchers a better understanding of
how similar proteins in organisms including plants and bacteria,
as well as proteins in the human body with similar functions
(called mechanosensitive ion channels), might operate.



FULL STORY ========================================================================== [Venus fly trap (stock | Credit: (c) Jane / stock.adobe.com] Venus fly
trap (stock image).

Credit: (c) Jane / stock.adobe.com [Venus fly trap (stock | Credit:
(c) Jane / stock.adobe.com] Venus fly trap (stock image).

Credit: (c) Jane / stock.adobe.com Close Scientists at Scripps Research
have revealed the three-dimensional structure of Flycatcher1, an aptly
named protein channel that may enable Venus fly trap plants to snap shut
in response to prey. The structure of Flycatcher1, published February 14
in Nature Communications, helps shed light on longstanding questions about
the remarkably sensitive touch response of Venus fly traps. The structure
also gives the researchers a better understanding of how similar proteins
in organisms including plants and bacteria, as well as proteins in the
human body with similar functions (called mechanosensitive ion channels),
might operate.


========================================================================== "Despite how different Venus fly traps are from humans, studying the
structure and function of these mechanosensitive channels gives us a
broader framework for understanding the ways that cells and organisms
respond to touch and pressure," says co-senior author and Scripps Research professor Andrew Ward, PhD.

"Every new mechanosensitive channel that we study helps us make progress
in understanding how these proteins can sense force and translate that to action and ultimately reveal more about human biology and health," adds co-senior author Ardem Patapoutian, PhD, a Scripps Research professor
who won the Nobel Prize in Physiology or Medicine for research on
the mechanosensitive channels that allow the body to sense touch and temperature.

Mechanosensitive ion channels are like tunnels that span the membranes
of cells. When jostled by movement, the channels open, letting charged molecules rush across. In response, cells then alter their behavior --
a neuron might signal its neighbor, for instance. The ability for cells
to sense pressure and movement is important for people's senses of touch
and hearing, but also for many internal body processes -- from the ability
of the bladder to sense that it's full to the ability of lungs to sense
how much air is being breathed.

Previously, scientists had homed in on three ion channels in Venus fly
traps thought to be related to the ability of the carnivorous plant to
snap its leaves shut when its sensitive trigger hairs get touched. One, Flycatcher1, caught researchers' attention because its genetic sequence
looked similar to a family of mechanosensitive channels, MscS, found
in bacteria.

"The fact that variants of this channel are found throughout evolution
tells us that it must have some fundamental, important functions that
have been maintained in different types of organisms," says co-first
author Sebastian Jojoa-Cruz, a graduate student at Scripps Research.



==========================================================================
In the new study, the researchers used cryo-electron microscopy --
a cutting- edge technique that reveals the locations of atoms within a
frozen protein sample -- to analyze the precise arrangement of molecules
that form the Flycatcher1 protein channel in Venus fly trap plants. They
found that Flycatcher1 is, in many ways, similar to bacterial MscS
proteins -- seven groups of identical helices surrounding a central
channel. But, unlike other MscS channels, Flycatcher1 has an unusual
linker region extending outward from each group of helices. Like a switch,
each linker can be flipped up or down.

When the team determined the structure of Flycatcher1, they found six
linkers in the down position, and just one flipped up.

"The architecture of Flycatcher1's channel core was similar to other
channels that have been studied for years, but these linker regions
were surprising," says Kei Saotome, PhD, a former postdoctoral research associate at Scripps Research and co-first author of the new paper.

To help elucidate the function of these switches, the researchers altered
the linker to disrupt the up position. Flycatcher1, they found, no longer functioned as usual in response to pressure; the channel remained open for
a longer duration when it would normally close upon removal of pressure.

"The profound effect of this mutation tells us that the conformations
of these seven linkers is likely relevant for how the channel works,"
says co-senior author Swetha Murthy, PhD, of Vollum Institute at Oregon
Health and Science University, a former postdoctoral research associate
at Scripps Research.

Now that they solved the molecular structure, the research team is
planning future studies on the function of Flycatcher1 to understand how different conformations affect its function. More work is also needed
to determine whether Flycatcher1 is solely responsible for the snapping
shut of Venus fly trap leaves, or whether other suspected channels play complementary roles.

In addition to Jojoa-Cruz, Saotome, Murthy, Patapoutian and Ward,
authors of the study, "Structural insights into the Venus flytrap mechanosensitive ion channel Flycatcher1," are Che Chun Alex Tsui and
Wen-Hsin Lee of Scripps Research, and Mark Sansom of University of Oxford.

This work and the researchers involved were supported by funding from the National Institutes of Health (R01 HL143297, R01 HL143297), a Ray Thomas Edwards Foundation grant, the Wellcome Trust (grant 208361/Z/17/Z),
the Biotechnology and Biological Sciences Research Council (grants
BB/N000145/1 and BB/R00126X/1), the Engineering and Physical Sciences
Research Council (grant EP/R004722/1), a postdoctoral fellowship from the
Jane Coffin Childs Memorial Fund for Medical Research, the Skaggs-Oxford Scholarship, the Croucher Foundation, and the Howard Hughes Medical
Institute.

========================================================================== Story Source: Materials provided by Scripps_Research_Institute. Note:
Content may be edited for style and length.


========================================================================== Related Multimedia:
*
Image_illustrating_structure_of_Venus_fly_trap's_mechanosensitive_ion
channel,_Flycatcher1 ========================================================================== Journal Reference:
1. Sebastian Jojoa-Cruz, Kei Saotome, Che Chun Alex Tsui, Wen-Hsin
Lee, Mark
S. P. Sansom, Swetha E. Murthy, Ardem Patapoutian, Andrew B. Ward.

Structural insights into the Venus flytrap mechanosensitive ion
channel Flycatcher1. Nature Communications, 2022; 13 (1) DOI:
10.1038/s41467-022- 28511-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220217141334.htm

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