Regulation of the stability of RGF1 receptor by the ubiquitin-specific proteases UBP12/UBP13 is critical for root meristem maintenance
Regulation of the stability of RGF1 receptor by the ubiquitin-specific proteases UBP12/UBP13 is critical for root meristem maintenance
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泛素特异性蛋白酶 UBP12/UBP13 对 RGF1 受体稳定性的调节对于根分生组织的维持至关重要
DOI：
10.1073/pnas.1714177115
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发表时间：
2018-01-30
影响因子：
11.1
通讯作者：
Tang, Wenqiang
中科院分区：
文献类型：
--
作者：
An, Zhichao;Liu, Yuliang;Tang, Wenqiang
意义可逆泛素化调节细胞蛋白丰度。受体样激酶（receptor-like kinase， RLK） RGFR1在调控根分生组织发育中起重要作用。在配体结合后，活化的RGFR1被泛素化，最终被26S蛋白酶体降解。在本研究中，我们发现泛素特异性蛋白酶UBP12和UBP13是RGFR1信号通路的组分。UBP13直接与RGFR1相互作用，可以抵消配体诱导的RGFR1的泛素化和降解。我们的发现为了解细胞表面RLKs的动态调控提供了见解，这可能有助于微调植物细胞对细胞外刺激的敏感性。根分生组织生长因子（RGF） 1是一种重要的调节根生长的肽激素。RGF1通过与其受体RGFR1结合，调节两种转录因子的表达，即over1和2 (PLT1/2)，从而影响根分生组织的发育。在这里，我们发现泛素特异性蛋白酶UBP12和UBP13是根分生组织发育的积极调节因子，并且UBP13直接与RGF1受体（RGFR1）及其同源物RGFR2相互作用。ubp12,13双突变根对外源RGF1完全不敏感。与此结果一致的是，rgf1诱导的RGFR1蛋白泛素化和转化在ubp12、13突变株中加速，而在过表达UBP13的转基因植株中延迟。遗传分析表明，PLT2或RGFR1过表达部分挽救了ubp12、13植株的短根表型和皮质根分生组织细胞数量的减少。总之，我们的研究结果表明，UBP12/13是RGF1- RGFR1 - plt1 /2信号通路的调节因子，并且UBP12/13可以抵消RGF1诱导的RGFR1泛素化，稳定RGFR1，并维持根细胞对RGF1的敏感性。
Significance Reversible ubiquitination regulates cellular protein abundance. The receptor-like kinase (RLK) RGFR1 plays an important role in regulating root meristem development. Upon ligand binding, activated RGFR1 is ubiquitinated and eventually degraded by the 26S proteasome. In this study, we found that the ubiquitin-specific proteases UBP12 and UBP13 are components of the RGFR1 signaling pathway. UBP13 interacts directly with RGFR1 and can counteract the ligand-induced ubiquitination and degradation of RGFR1. Our discovery provides insight into the dynamic regulation of cell-surface RLKs, which may serve to fine-tune the sensitivity of plant cells to extracellular stimuli. ROOT MERISTEM GROWTH FACTOR (RGF) 1 is an important peptide hormone that regulates root growth. Upon binding to its receptor, RGFR1, RGF1 regulates the expression of two transcription factors, PLETHORA 1 and 2 (PLT1/2), to influence root meristem development. Here, we show that the ubiquitin-specific proteases UBP12 and UBP13 are positive regulators of root meristem development and that UBP13 interacts directly with RGF1 receptor (RGFR1) and its close homolog RGFR2. The ubp12,13 double-mutant root is completely insensitive to exogenous applied RGF1. Consistent with this result, RGF1-induced ubiquitination and turnover of RGFR1 protein were accelerated in ubp12,13-mutant plants but were delayed in transgenic plants overexpressing UBP13. Genetic analysis showed that PLT2 or RGFR1 overexpression partially rescued the short-root phenotype and the reduced cortical root meristem cell number in ubp12,13 plants. Together, our results demonstrate that UBP12/13 are regulators of the RGF1–RGFR1–PLT1/2 signaling pathway and that UBP12/13 can counteract RGF1-induced RGFR1 ubiquitination, stabilize RGFR1, and maintain root cell sensitivity to RGF1.