MAP Kinase 6-mediated activation of vacuolar processing enzyme modulates heat shock-induced programmed cell death in Arabidopsis
MAP Kinase 6-mediated activation of vacuolar processing enzyme modulates heat shock-induced programmed cell death in Arabidopsis
复制标题
DOI：
10.1111/j.1469-8137.2012.04131.x
复制
发表时间：
2012-07-01
期刊：
影响因子：
9.4
通讯作者：
Xing, Da
中科院分区：
文献类型：
--
作者：
Li, Zhe;Yue, Haiyun;Xing, Da
液泡加工酶（VPE）是一种半胱氨酸蛋白酶，在植物超敏性细胞死亡中得到了广泛的研究，但VPE在非生物胁迫下的作用和分子机制尚不清楚。本研究探讨了VPEs在拟南芥热应激反应中的作用。热休克（HS）下拟南芥VPE活性和？VPE都是上调的，并且？在hs诱导的程序性细胞死亡（PCD）中，VPE缺乏抑制空泡破坏和延迟caspase-3样活化。此外，HS处理下VPE活性的变化与caspase-1样活性的变化基本一致，说明HS诱导的VPE活性可能具有caspase-1样活性。进一步的研究表明，HS处理后MAP激酶6 （MPK6）活性增加，抑制剂和突变体的实验表明MPK6负责？HS处理后VPE活化。在HS胁迫下，活性氧（ROS）的产生、细胞质钙浓度（[Ca2+]cyt）的增加和钙调蛋白3 （CaM3）转录物水平的上调发生在MPK6激活的上游。我们的研究结果表明，拟南芥？VPE是由MPK6介导的，在hs诱导的拟南芥PCD中发挥重要作用，为植物VPE的机制研究提供了新的思路。
Vacuolar processing enzyme (VPE), a cysteine protease, has been intensively studied in plant hypersensitive cell death, but the role and molecular mechanism of VPEs in response to abiotic stresses remain unclear. This work investigated the involvement of VPEs in Arabidopsis response to heat stress. Under heat shock (HS), Arabidopsis VPE activity and the transcript level of ?VPE were both upregulated, and ?VPE deficiency suppressed vacuolar disruption and delayed caspase-3-like activation in HS-induced programmed cell death (PCD). Moreover, the change of VPE activity generally paralleled the alteration of caspase-1-like activity under HS treatment, indicating that HS-induced VPE activity might exhibit the caspase-1-like activity. Further studies showed that MAP Kinase 6 (MPK6) activity was increased after HS treatment, and experiments with inhibitors and mutants suggested that MPK6 was responsible for the ?VPE activation after HS treatment. In response to HS stress, reactive oxygen species (ROS) production, increase of cytoplasmic calcium concentration ([Ca2+]cyt) and the upregulation of calmodulin 3 (CaM3) transcript level occurred upstream of MPK6 activation. Our results suggested that activation of Arabidopsis ?VPE was mediated by MPK6 and played an important role in HS-induced Arabidopsis PCD, providing new insight into the mechanistic study of plant VPEs.