Mechanosensitive channels are activated by stress in the actin stress fibers, which could be involved in gravity sensing in plants
Mechanosensitive channels are activated by stress in the actin stress fibers, which could be involved in gravity sensing in plants
复制标题
机械敏感通道由肌动蛋白应力纤维中的应力激活，这可能参与植物的重力感应
DOI：
10.1111/plb.12095
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发表时间：
2014
期刊：
影响因子：
3.9
通讯作者：
and Hidetoshi Iida
中科院分区：
文献类型：
--
作者：
Hitoshi Tatsumi;Takuya Furuichi;Masataka Nakano;Masatsugu Toyota;Kimihide Hayakawa;Masahiro Sokabe;and Hidetoshi Iida
机械敏感(MS)通道在多种细胞中表达。MS通道活动调控的分子和生物物理机制是基础生物学的研究热点。MS通道被认为在植物细胞的重力感应中起着至关重要的作用。到目前为止，已经提出了两种MS通道激活机制。其一是脂质双层中的张力发展直接激活MS通道。第二种机制认为，细胞骨架参与了通道的激活，因为MS通道的活动受到影响细胞骨架的药物处理的调节。我们测试了细胞骨架中的张力是否激活了MS通道。向哺乳动物内皮细胞显微注射鬼臼蛋白偶联的珠子，这些珠子结合到应力纤维上，并通过光钳拖动珠子对肌动蛋白细胞骨架施加牵引力。当施加外力时，MS通道被激活，这表明对肌动蛋白细丝的亚PN力激活了单个MS通道。植物在重力感应中可能使用类似的分子机制，因为重力载体变化引起的细胞质钙离子浓度增加被潜在的MS通道抑制剂和肌动蛋白干扰药物减弱。这些结果支持这样一种观点，即依赖于重力的淀粉体沉积导致肌动蛋白细丝张力增加，激活了MS钙离子通透通道，这可能是重力刺激引起钙离子浓度升高的分子机制。我们综述了肌动蛋白细丝和MS通道利用先进的生物物理方法进行张力传感的最新研究进展，并讨论了它们在重力传感中的可能作用。
Mechanosensitive (MS) channels are expressed in a variety of cells. The molecular and biophysical mechanism involved in the regulation of MS channel activities is a central interest in basic biology. MS channels are thought to play crucial roles in gravity sensing in plant cells. To date, two mechanisms have been proposed for MS channel activation. One is that tension development in the lipid bilayer directly activates MS channels. The second mechanism proposes that the cytoskeleton is involved in the channel activation, because MS channel activities are modulated by pharmacological treatments that affect the cytoskeleton. We tested whether tension in the cytoskeleton activates MS channels. Mammalian endothelial cells were microinjected with phalloidin‐conjugated beads, which bound to stress fibres, and a traction force to the actin cytoskeleton was applied by dragging the beads with optical tweezers. MS channels were activated when the force was applied, demonstrating that a sub‐pN force to the actin filaments activates a single MS channel. Plants may use a similar molecular mechanism in gravity sensing, since the cytoplasmic Ca2+concentration increase induced by changes in the gravity vector was attenuated by potential MS channel inhibitors, and by actin‐disrupting drugs. These results support the idea that the tension increase in actin filaments by gravity‐dependent sedimentation of amyloplasts activates MS Ca2+‐permeable channels, which can be the molecular mechanism of a Ca2+concentration increase through gravistimulation. We review recent progress in the study of tension sensing by actin filaments and MS channels using advanced biophysical methods, and discuss their possible roles in gravisensing.