Department of Plant Physiology and Biochemistry, St. Petersburg State University, 199034 St. Petersburg, Russia.
J Plant Physiol. 2010 Apr 15;167(6):417-22. doi: 10.1016/j.jplph.2009.12.014. Epub 2010 Feb 21.
An important question in modern plant biology concerns the mechanisms of auxin perception. Despite the recently discovered soluble receptor, the F-box protein TIR1, there is no doubt that another type of signal perception exists, and is linked to the plasma membrane. Two models for the receptor have been suggested: either the receptor includes a protein kinase, or it is coupled with a G-protein. We propose a third model, acting through Ca(2+)-channels in the plasma membrane. The model is based on the revealed rapid auxin-induced reactions, including changes in the membrane potential, shifts in cytosol concentration of Ca(2+) and H(+) and modulation of cell sensitivity to hormones by the external Ca(2+) concentration. Detailed inhibitor analysis with both living cells and isolated plasma membranes show that auxin might directly stimulate Ca(2+) transport through the plasma membrane. A hypothetical scheme of auxin perception at the plasma membrane is suggested together with further transduction events. In addition, comparative analyses of auxin and serotonin perceptions are provided.
现代植物生物学中的一个重要问题涉及生长素感应的机制。尽管最近发现了可溶性受体、F -box 蛋白 TIR1，但毫无疑问，另一种类型的信号感应存在，并且与质膜相连。已经提出了两种受体模型：要么受体包含蛋白激酶，要么它与 G 蛋白偶联。我们提出了第三种模型，通过质膜中的 Ca(2+)通道起作用。该模型基于揭示的快速生长素诱导反应，包括膜电位变化、细胞质中 Ca(2+)和 H(+)浓度的变化以及细胞对外界 Ca(2+)浓度的激素敏感性的调节。用活细胞和分离的质膜进行的详细抑制剂分析表明，生长素可能直接刺激质膜中的 Ca(2+)转运。提出了一种质膜上生长素感应的假设方案以及进一步的转导事件。此外，还提供了生长素和血清素感应的比较分析。
