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Arabidopsis plasma membrane protein crucial for Ca2+ influx and touch sensing in roots

  • Yuko Nakagawa
  • Takeshi Katagiri
  • Kazuo Shinozaki
  • Zhi Qi
  • Hitoshi Tatsumi
  • Takuya Furuichi
  • Akio Kishigami
  • Masahiro Sokabe
  • Itaru Kojima
  • Shusei Sato
  • Tomohiko Kato
  • Satoshi Tabata
  • Kazuko Iida
  • Asuka Terashima
  • Masataka Nakano
  • Mitsunobu Ikeda
  • Takuya Yamanaka
  • Hidetoshi Iida
National Academy of Sciences
Publication Date
Feb 20, 2007
  • Biology
  • Design


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 Ca2+-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 Ca2+ influx with mechanosensing in Arabidopsis thaliana. MCA1 cDNA was cloned by the functional complementation of lethality of a yeast mid1 mutant lacking a putative Ca2+-permeable SA channel component. Mca1 was localized to the yeast plasma membrane as an integral membrane protein and mediated Ca2+ influx. Mca1 also increased [Ca2+]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 Ca2+-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.


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