PT  - JOURNAL ARTICLE
AU  - Codjoe, Jennette M.
AU  - Richardson, Ryan A.
AU  - Haswell, Elizabeth S.
TI  - Unbiased proteomic and forward genetic screens reveal that mechanosensitive ion channel MSL10 functions at ER-plasma membrane contact sites in <em>Arabidopsis thaliana</em>
AID  - 10.1101/2022.05.23.493056
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.05.23.493056
4099  - http://biorxiv.org/content/early/2022/05/23/2022.05.23.493056.short
4100  - http://biorxiv.org/content/early/2022/05/23/2022.05.23.493056.full
AB  - Mechanosensitive (MS) ion channels are an evolutionarily conserved way for cells to sense mechanical forces and transduce them into ionic signals. The channel properties of Arabidopsis thaliana MscS-Like (MSL)10 have been well studied, but how MSL10 signals remains largely unknown. To uncover signaling partners of MSL10, we employed both a proteomic screen and a forward genetic screen; both unexpectedly implicated ER-plasma membrane contact sites (EPCSs) in MSL10 function. The proteomic screen revealed that MSL10 associates with multiple proteins associated with EPCSs. Of these, only VAMP-associated proteins (VAP)27-1 and VAP27-3 interacted directly with MSL10. The forward genetic screen, for suppressors of a gain-of-function MSL10 allele (msl10-3G, MSL10S640L), identified mutations in the synaptotagmin (SYT)5 and SYT7 genes. We also found that EPCSs were expanded in leaves of msl10-3G plants compared to the wild type. Taken together, these results indicate that MSL10 can be found at EPCSs and functions there, providing a new cell-level framework for understanding MSL10 signaling. In addition, placing a mechanosensory protein at EPCS provides new insight into the function and regulation of this type of subcellular compartment.Competing Interest StatementThe authors have declared no competing interest.