title: Arabidopsis MSL10 has a regulated cell death signaling activity that is separable from its mechanosensitive ion channel activity.
abstract: Members of the MscS superfamily of mechanosensitive ion channels function as osmotic safety valves, releasing osmolytes under increased membrane tension. MscS homologs exhibit diverse topology and domain structure, and it has been proposed that the more complex members of the family might have novel regulatory mechanisms or molecular functions. Here, we present a study of MscS-Like (MSL)10 from Arabidopsis thaliana that supports these ideas. High-level expression of MSL10-GFP in Arabidopsis induced small stature, hydrogen peroxide accumulation, ectopic cell death, and reactive oxygen species- and cell death-associated gene expression. Phosphomimetic mutations in the MSL10 N-terminal domain prevented these phenotypes. The phosphorylation state of MSL10 also regulated its ability to induce cell death when transiently expressed in Nicotiana benthamiana leaves but did not affect subcellular localization, assembly, or channel behavior. Finally, the N-terminal domain of MSL10 was sufficient to induce cell death in tobacco, independent of phosphorylation state. We conclude that the plant-specific N-terminal domain of MSL10 is capable of inducing cell death, this activity is regulated by phosphorylation, and MSL10 has two separable activities-one as an ion channel and one as an inducer of cell death. These findings further our understanding of the evolution and significance of mechanosensitive ion channels.
authors: Department of Biology, Washington University, St. Louis, Missouri 63130.
authors: Kira M
authors: KM
authors: Veley
authors: Department of Biology, Washington University, St. Louis, Missouri 63130.
authors: Grigory
authors: G
authors: Maksaev
authors: Department of Biology, Washington University, St. Louis, Missouri 63130.
authors: Elizabeth M
authors: EM
authors: Frick
authors: Department of Biology, Washington University, St. Louis, Missouri 63130.
authors: Emma
authors: E
authors: January
authors: Department of Biology, Washington University, St. Louis, Missouri 63130.
authors: Sarah C
authors: SC
authors: Kloepper
authors: Department of Biology, Washington University, St. Louis, Missouri 63130 ehaswell@wustl.edu.
authors: Elizabeth S
authors: ES
authors: Haswell
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death; D019143:Evolution, Molecular; D015870:Gene Expression; D017930:Genes, Reporter; D006861:Hydrogen Peroxide / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D009154:Mutation; D010766:Phosphorylation; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D017382:Reactive Oxygen Species / Q000378:metabolism; D011993:Recombinant Fusion Proteins; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction; D014026:Nicotiana / Q000166:cytology / Q000235:genetics / Q000502:physiology; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D007473:Ion Channels; C530361:MSL10 protein, Arabidopsis; D008565:Membrane Proteins; D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins; D006861:Hydrogen Peroxide