Mizuno Takeshi, Nakamichi Norihito
Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya, 464-8601 Japan.
Plant Cell Physiol. 2005 May;46(5):677-85. doi: 10.1093/pcp/pci087. Epub 2005 Mar 13.
In Arabidopsis thaliana, AUTHENTIC RESPONSE REGULATORS (ARRs) act as downstream components of the His-to-Asp phosphorelay (two-component) signaling pathway that is propagated primarily by the cytokinin receptor kinases, AUTHENTIC HIS-KINASES (AHK2, AHK3 and AHK4/CRE1). Thus, this bacterial type of signaling system is essential for responses to a class of hormones in plants. Interestingly, this higher plant has also evolved its own atypical (or unique) variants of two-component signal transducers, PSEUDO-RESPONSE REGULATORS (PRRs). Several lines of recent results suggest that the functions of PRRs are closely relevant to the plant clock (oscillator) that is central to circadian rhythms, the underlying mechanisms of which have long been the subject of debate. Through an overview of recent results, the main issue addressed here is whether or not the pseudo-response regulators (PRRs) are true oscillator components (TOCs).
在拟南芥中，正宗反应调节因子（ARR）作为组氨酸到天冬氨酸磷酸化传递（双组分）信号通路的下游组分，该信号通路主要由细胞分裂素受体激酶——正宗组氨酸激酶（AHK2、AHK3和AHK4/CRE1）进行传递。因此，这种细菌类型的信号系统对于植物对一类激素的反应至关重要。有趣的是，这种高等植物还进化出了自身双组分信号转导器的非典型（或独特）变体——伪反应调节因子（PRR）。最近的几项研究结果表明，PRR的功能与植物生物钟（振荡器）密切相关，而生物钟是昼夜节律的核心，其潜在机制长期以来一直是争论的焦点。通过对近期研究结果的概述，本文探讨的主要问题是伪反应调节因子（PRR）是否为真正的振荡器组分（TOC）。
