Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Quebec, Quebec, Canada.
Plant Physiol. 2011 Nov;157(3):1379-93. doi: 10.1104/pp.111.178343. Epub 2011 Aug 26.
Mitogen-activated protein kinases (MAPKs) contribute to the establishment of plant disease resistance by regulating downstream signaling components, including transcription factors. In this study, we identified MAPK-interacting proteins, and among the newly discovered candidates was a Cys-2/His-2-type zinc finger protein named PtiZFP1. This putative transcription factor belongs to a family of transcriptional repressors that rely on an ERF-associated amphiphilic repression (EAR) motif for their repression activity. Amino acids located within this repression motif were also found to be essential for MAPK binding. Close examination of the primary protein sequence revealed a functional bipartite MAPK docking site that partially overlaps with the EAR motif. Transient expression assays in Arabidopsis (Arabidopsis thaliana) protoplasts suggest that MAPKs promote PtiZFP1 degradation through the 26S proteasome. Since features of the MAPK docking site are conserved among other EAR repressors, our study suggests a novel mode of defense mechanism regulation involving stress-responsive MAPKs and EAR repressors.
丝裂原活化蛋白激酶（MAPK）通过调节下游信号转导成分（包括转录因子）参与植物疾病抗性的建立。在这项研究中，我们鉴定了 MAPK 相互作用蛋白，在新发现的候选蛋白中有一种 Cys-2/His-2 型锌指蛋白，命名为 PtiZFP1。这个假定的转录因子属于转录抑制因子家族，依赖 ERF 相关的两亲性抑制（EAR）基序发挥抑制活性。该抑制基序内的氨基酸对于 MAPK 结合也是必需的。对该蛋白一级序列的仔细检查发现了一个功能上的二分法 MAPK 对接位点，该位点与 EAR 基序部分重叠。在拟南芥原生质体中的瞬时表达试验表明，MAPK 通过 26S 蛋白酶体促进 PtiZFP1 的降解。由于 MAPK 对接位点的特征在其他 EAR 抑制剂中是保守的，因此我们的研究表明了一种新的涉及应激响应 MAPK 和 EAR 抑制剂的防御机制调节模式。
