title: Arabidopsis plasma membrane protein crucial for Ca2+ influx and touch sensing in roots.
abstract: Plants can sense and respond to mechanical stimuli, like animals. An early mechanism of mechanosensing and response is speculated to be governed by as-yet-unidentified sensory complexes containing a Ca(2+)-permeable, stretch-activated (SA) channel. However, the components or regulators of such complexes are poorly understood at the molecular level in plants. Here, we report the molecular identification of a plasma membrane protein (designated Mca1) that correlates Ca(2+) influx with mechanosensing in Arabidopsis thaliana. MCA1 cDNA was cloned by the functional complementation of lethality of a yeast mid1 mutant lacking a putative Ca(2+)-permeable SA channel component. Mca1 was localized to the yeast plasma membrane as an integral membrane protein and mediated Ca(2+) influx. Mca1 also increased [Ca(2+)](cyt) upon plasma membrane distortion in Arabidopsis. The growth of MCA1-overexpressing plants was impaired in a high-calcium but not a low-calcium medium. The primary roots of mca1-null plants failed to penetrate a harder agar medium from a softer one. These observations demonstrate that Mca1 plays a crucial role in a Ca(2+)-permeable SA channel system that leads to mechanosensing in Arabidopsis. We anticipate our findings to be a starting point for a deeper understanding of the molecular mechanisms of mechanotransduction in plants.
authors.affiliation: Department of Biology, Tokyo Gakugei University, Tokyo 184-8501, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Nakagawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Katagiri
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shinozaki
authors.forename: Zhi
authors.initials: Z
authors.lastname: Qi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tatsumi
authors.forename: Takuya
authors.initials: T
authors.lastname: Furuichi
authors.forename: Akio
authors.initials: A
authors.lastname: Kishigami
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sokabe
authors.forename: Itaru
authors.initials: I
authors.lastname: Kojima
authors.forename: Shusei
authors.initials: S
authors.lastname: Sato
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Kato
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tabata
authors.forename: Kazuko
authors.initials: K
authors.lastname: Iida
authors.forename: Asuka
authors.initials: A
authors.lastname: Terashima
authors.forename: Masataka
authors.initials: M
authors.lastname: Nakano
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Ikeda
authors.forename: Takuya
authors.initials: T
authors.lastname: Yamanaka
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Iida
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D015152:Blotting, Northern; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000235:genetics*; D003001:Cloning, Molecular; D040461:Gene Components; D005816:Genetic Complementation Test; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA
chemical_list: D029681:Arabidopsis Proteins; D015220:Calcium Channels; C520286:MCA1 protein, Arabidopsis; D008565:Membrane Proteins; D002118:Calcium