Two MscS homologs provide mechanosensitive channel activities in the Arabidopsis root.
In bacterial and animal systems, mechanosensitive (MS) ion channels are thought to mediate the perception of pressure, touch, and sound [1-3]. Although plants respond to a wide variety of mechanical stimuli, and although many mechanosensitive channel activities have been characterized in plant membranes by the patch-clamp method, the molecular nature of mechanoperception in plant systems has remained elusive [4]. Likely candidates are relatives of MscS (Mechanosensitive channel of small conductance), a well-characterized MS channel that serves to protect E. coli from osmotic shock [5]. Ten MscS-Like (MSL) proteins are found in the genome of the model flowering plant Arabidopsis thaliana[4, 6, 7]. MSL2 and MSL3, along with MSC1, a MscS family member from green algae, are implicated in the control of organelle morphology [8, 9]. Here, we characterize MSL9 and MSL10, two MSL proteins found in the plasma membrane of root cells. We use a combined genetic and electrophysiological approach to show that MSL9 and MSL10, along with three other members of the MSL family, are required for MS channel activities detected in protoplasts derived from root cells. This is the first molecular identification and characterization of MS channels in plant membranes.
Haswell
Elizabeth S
ES
Division of Biology 156-29, California Institute of Technology, Pasadena, California 91125. Electronic address: ehaswell@wustl.edu.
Peyronnet
Rémi
R
Institut des Sciences du Végétal, Centre National de la Recherche Scientifique, UPR 2355, Avenue de la Terrasse, 91198 Gif sur Yvette Cedex, France.
Barbier-Brygoo
Hélène
H
Institut des Sciences du Végétal, Centre National de la Recherche Scientifique, UPR 2355, Avenue de la Terrasse, 91198 Gif sur Yvette Cedex, France.
Meyerowitz
Elliot M
EM
Division of Biology 156-29, California Institute of Technology, Pasadena, California 91125.
Frachisse
Jean-Marie
JM
Institut des Sciences du Végétal, Centre National de la Recherche Scientifique, UPR 2355, Avenue de la Terrasse, 91198 Gif sur Yvette Cedex, France.
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D040542:Mechanotransduction, Cellular; D008565:Membrane Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D018517:Plant Roots / Q000378:metabolism*; D011523:Protoplasts / Q000378:metabolism
D029681:Arabidopsis Proteins; C530361:MSL10 protein, Arabidopsis; C530360:MSL9 protein, Arabidopsis; D008565:Membrane Proteins