Plant & zo
The science of plants and more
Sometimes you will need new leads. Like for the question how the signal from mechanosensitive channels is transferred to the rest of the plant. A research group from the US went searching for those new leads to answer this question.
Mechanosensitive channels are membrane proteins which let through a signal after the membrane changes form, like when a barrier presses into it. This signal is often in the form of an ion, like Ca2+. After letting through the signal, researchers observe that an adaptation, like change of direction of growth, takes place. But what is actually picking up this ionic signal and translates it in a concrete action is unknown.
To find out researchers studied which proteins are binding the mechanosensitive channel MSL10. This gave them a long list of proteins. But zooming in on the proteins that most frequently bind MSL10 the researchers noticed that these were part of ER-plasma membrane contact sites. Like VAP27-1, VAP27-2, and SYT1. Closer study showed that only the ER localised VAP27-1 and VAP27-3 directly bind to plasma membrane localised MSL10. With the actual interaction between VAP27-1/VAP27-3 and MSL10 creating an ER-plasma membrane contact site.
ER-plasma membrane contact sites are playing an important role in the recognition of the signal
At the same time, the researchers analysed which genes are needed to transfer the signal that MSL10 lets through into concrete action. For this the researchers used plants that have a form of MSL10 that always lets signals through. As a consequence, these plants are shorter than normal. They mutated the plants using a chemical mutagen and selected the offspring of those plants that were taller. In some of these plants the MSL10 gene was back into its normal form. But two of these plants had a mutation in a different gene, SYT5 and SYT7. Both SYT5 and SYT7 are like SYT1 present in ER-plasma membrane contact sites. From the mutant analysis it turned out that when SYT5 or SYT7 are not working properly the signal of MSL10 is not properly received by the cell.
By far the most question around MSL10 and the signals it lets through have been answered. But this researcher shows that ER-plasma membrane contact sites are playing an important role in the translation of the signal into action. Enough new leads to keep the researchers going.
Jennette M Codjoe, Ryan A Richardson, Fionn McLoughlin, Richard David Vierstra, Elizabeth S Haswell (2022) Unbiased proteomic and forward genetic screens reveal that mechanosensitive ion channel MSL10 functions at ER–plasma membrane contact sites in Arabidopsis thaliana eLife 11:e80501, https://doi.org/10.7554/eLife.80501