Reevaluation of the CLV3-receptor interaction in the shoot apical meristem: dissection of the CLV3 signaling pathway from a direct ligand-binding point of view
Reevaluation of the CLV3-receptor interaction in the shoot apical meristem: dissection of the CLV3 signaling pathway from a direct ligand-binding point of view
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DOI：
10.1111/tpj.12817
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发表时间：
2015-04-01
期刊：
影响因子：
7.2
通讯作者：
Matsubayashi, Yoshikatsu
中科院分区：
文献类型：
--
作者：
Shinohara, Hidefumi;Matsubayashi, Yoshikatsu
CLAVATA 信号通路是拟南芥中控制干细胞更新和分化的网络的关键组成部分。 CLAVATA3 (CLV3) 是一种翻译后阿拉伯糖基化的分泌肽信号，可调节 WUSHEL (WUS) 转录，从而影响茎尖分生组织 (SAM) 中干细胞分化和增殖的平衡。已知参与 CLV3 信号传导感知的膜定位受体包括 CLV1、CLV2/CORYNE (CRN) 复合物和 RPK2。 CLV3肽可直接与CLV1结合；然而，尚不清楚 CLV3 肽是否直接与 CLV2 或 RPK2 结合。在本研究中，我们通过光活化阿拉伯糖化 CLV3 的光亲和标记重新评估了 CLV3 与其受体之间的直接相互作用。我们发现 CLV2 和 RPK2 没有与 CLV3 肽直接结合。进一步分析表明受体激酶BAM1直接结合CLV3肽。功能丧失的 clv1 bam1 双突变体表现出大量干细胞积聚在 SAM 中，并且对阿拉伯糖化 CLV3 肽的外源处理不敏感。 clv1 bam1 双突变体中 WUS 基因转录本上调，SAM 处 WUS 表达区域扩大。这些结果表明CLV1和BAM1是直接受体，足以影响控制SAM中干细胞数量的调节网络。相比之下，CLV2/CRN 复合物和 RPK2 不参与直接配体相互作用，但可能充当辅助受体。 意义说明 我们通过光亲和标记重新评估了 CLV3 与其受体之间的直接相互作用。受体激酶BAM1可以直接结合CLV3肽以及CLV1。功能丧失的 clv1 bam1 双突变体表现出大量干细胞积聚在 SAM 中，并且对阿拉伯糖化的 CLV3 不敏感。这些结果表明CLV1和BAM1是直接受体，足以影响控制SAM中干细胞数量的调节网络。
The CLAVATA signaling pathway is a key component of the network that controls stem cell renewal and differentiation in Arabidopsis thaliana. CLAVATA3 (CLV3) is a post-translationally arabinosylated secreted peptide signal that regulates WUSHEL (WUS) transcription to affect the balance of stem cell differentiation and proliferation in the shoot apical meristem (SAM). Known membrane-localized receptors involved in the perception of CLV3 signaling include CLV1, the CLV2/CORYNE (CRN) complex and RPK2. The CLV3 peptide can directly bind to CLV1; however, it is unclear whether the CLV3 peptide directly binds to CLV2 or RPK2. In this study, we re-evaluated the direct interaction between CLV3 and its receptors by photoaffinity labeling with photoactivatable arabinosylated CLV3. We showed that CLV2 and RPK2 exhibited no direct binding to the CLV3 peptide. Further analysis showed that the receptor kinase BAM1 directly binds the CLV3 peptide. A loss-of-function clv1 bam1 double mutant exhibited a large number of stem cells that accumulated in the SAM and was insensitive to exogenous treatment with the arabinosylated CLV3 peptide. WUS gene transcripts were up-regulated, and the region of WUS expression was enlarged at the SAM in the clv1 bam1 double mutant. These results indicate that CLV1 and BAM1 are direct receptors that are sufficient to affect the regulatory network controlling stem cell number in the SAM. In contrast, the CLV2/CRN complex and RPK2 are not involved in direct ligand interactions but may act as co-receptors.Significance Statement We re-evaluated the direct interaction between CLV3 and its receptors by photoaffinity labeling. The receptor kinase BAM1 could directly bind CLV3 peptide as well as CLV1. A loss-of-function clv1 bam1 double mutant exhibited a large number of stem cells that accumulated in the SAM and was insensitive to arabinosylated CLV3. These results indicate that CLV1 and BAM1 are direct receptors that are sufficient to affect the regulatory network controlling stem cell number in the SAM.