Gross Inonge, Durner Jörg
Nitric Oxide Production and Signalling Group, Institute of Biochemical Plant Pathology, Helmholtz Center Munich Germany.
Nitric Oxide Production and Signalling Group, Institute of Biochemical Plant Pathology, Helmholtz Center MunichGermany; Chair of Biochemical Plant Pathology, Technische Universität München, FreisingGermany.
Front Plant Sci. 2016 May 6;7:576. doi: 10.3389/fpls.2016.00576. eCollection 2016.
In plants, nitric oxide (NO)-mediated 3', 5'-cyclic guanosine monophosphate (cGMP) synthesis plays an important role during pathogenic stress response, stomata closure upon osmotic stress, the development of adventitious roots and transcript regulation. The NO-cGMP dependent pathway is well characterized in mammals. The binding of NO to soluble guanylate cyclase enzymes (GCs) initiates the synthesis of cGMP from guanosine triphosphate. The produced cGMP alters various cellular responses, such as the function of protein kinase activity, cyclic nucleotide gated ion channels and cGMP-regulated phosphodiesterases. The signal generated by the second messenger is terminated by 3', 5'-cyclic nucleotide phosphodiesterase (PDEs) enzymes that hydrolyze cGMP to a non-cyclic 5'-guanosine monophosphate. To date, no homologues of mammalian cGMP-synthesizing and degrading enzymes have been found in higher plants. In the last decade, six receptor proteins from Arabidopsis thaliana have been reported to have guanylate cyclase activity in vitro. Of the six receptors, one was shown to be a NO dependent guanylate cyclase enzyme (NOGC1). However, the role of these proteins in planta remains to be elucidated. Enzymes involved in the degradation of cGMP remain elusive, albeit, PDE activity has been detected in crude protein extracts from various plants. Additionally, several research groups have partially purified and characterized PDE enzymatic activity from crude protein extracts. In this review, we focus on presenting advances toward the identification of enzymes involved in the cGMP metabolism pathway in higher plants.
在植物中，一氧化氮（NO）介导的3',5'-环鸟苷单磷酸（cGMP）合成在病原胁迫反应、渗透胁迫下气孔关闭、不定根发育和转录调控过程中发挥着重要作用。NO-cGMP依赖途径在哺乳动物中已得到充分表征。NO与可溶性鸟苷酸环化酶（GCs）结合，引发三磷酸鸟苷合成cGMP。产生的cGMP改变各种细胞反应，如蛋白激酶活性、环核苷酸门控离子通道和cGMP调节的磷酸二酯酶的功能。第二信使产生的信号由3',5'-环核苷酸磷酸二酯酶（PDEs）终止，该酶将cGMP水解为非环化的5'-鸟苷单磷酸。迄今为止，在高等植物中尚未发现哺乳动物cGMP合成和降解酶的同源物。在过去十年中，已报道拟南芥中的六种受体蛋白在体外具有鸟苷酸环化酶活性。在这六种受体中，有一种被证明是NO依赖的鸟苷酸环化酶（NOGC1）。然而，这些蛋白在植物中的作用仍有待阐明。尽管已在各种植物的粗蛋白提取物中检测到PDE活性，但参与cGMP降解的酶仍然未知。此外，几个研究小组已从粗蛋白提取物中部分纯化并表征了PDE酶活性。在本综述中，我们重点介绍在鉴定高等植物中参与cGMP代谢途径的酶方面取得的进展。
