CAST AWAY, a Membrane-Associated Receptor-Like Kinase, Inhibits Organ Abscission in Arabidopsis
CAST AWAY, a Membrane-Associated Receptor-Like Kinase, Inhibits Organ Abscission in Arabidopsis
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DOI：
10.1104/pp.111.175224
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发表时间：
2011-08-01
期刊：
影响因子：
7.4
通讯作者：
Liljegren, Sarah J.
中科院分区：
文献类型：
--
作者：
Burr, Christian A.;Leslie, Michelle E.;Liljegren, Sarah J.
受体样激酶介导的细胞信号通路在植物生长发育的许多方面发挥着重要作用。一对拟南芥富含亮氨酸重复序列受体样蛋白(LRR-RLKs)，HAESA(HAE)和HAESA-LIKE2(HSL2)，被证明激活了导致器官脱落的细胞分离过程。另一对LRR-RLK，EVR和体细胞胚胎发生受体样激酶1，可能通过调节HAE/HSL2的活性而作为脱落的抑制因子。这些RLK进入和离开细胞表面的循环可能受到NEVERSHED(NEV)的调控，NEV是一种膜运输调节因子，对器官脱落至关重要。我们在这里报告了Cst(Cst)的特征，CST是一种受体样胞浆激酶，起到了细胞分离的空间抑制作用。CST的破坏抑制了NEV突变花的脱落缺陷，并恢复了NEV离解区中跨高尔基体网络的离散特性。器官脱落后，Nev CST花的离区变大，边界模糊。我们发现，CST在体外是一种双特异性的激酶，其氨基末端的肉豆蔻酰化促进了与质膜的结合。利用双分子荧光互补分析，我们检测到CST与HAE和EVR在拟南芥原生质体质膜上的相互作用，并假设CST直接和间接地负调控细胞分离信号。提出了一个在器官分离过程中整合受体样激酶信号和膜转运的潜在作用的模型。
Receptor-like kinase-mediated cell signaling pathways play fundamental roles in many aspects of plant growth and development. A pair of Arabidopsis (Arabidopsis thaliana) leucine-rich repeat receptor-like kinases (LRR-RLKs), HAESA (HAE) and HAESA-LIKE2 (HSL2), have been shown to activate the cell separation process that leads to organ abscission. Another pair of LRR-RLKs, EVERSHED (EVR) and SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE1, act as inhibitors of abscission, potentially by modulating HAE/HSL2 activity. Cycling of these RLKs to and from the cell surface may be regulated by NEVERSHED (NEV), a membrane trafficking regulator that is essential for organ abscission. We report here the characterization of CAST AWAY (CST), a receptor-like cytoplasmic kinase that acts as a spatial inhibitor of cell separation. Disruption of CST suppresses the abscission defects of nev mutant flowers and restores the discrete identity of the trans-Golgi network in nev abscission zones. After organ shedding, enlarged abscission zones with obscured boundaries are found in nev cst flowers. We show that CST is a dual-specificity kinase in vitro and that myristoylation at its amino terminus promotes association with the plasma membrane. Using the bimolecular fluorescence complementation assay, we have detected interactions of CST with HAE and EVR at the plasma membrane of Arabidopsis protoplasts and hypothesize that CST negatively regulates cell separation signaling directly and indirectly. A model integrating the potential roles of receptor-like kinase signaling and membrane trafficking during organ separation is presented.