Institute of Biochemical Plant Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
Plant Signal Behav. 2020;15(2):1716512. doi: 10.1080/15592324.2020.1716512. Epub 2020 Jan 27.
The plant hormone ethylene is a key regulator of growth, development and stress adaptation at all stages of the plant life cycle. Signal perception and response to the plant hormone are mediated by a family of receptor kinases localized at the ER-Golgi network which gain their high affinity and specificity for the chemically simple ethylene molecule by an essential copper cofactor bound at their transmembrane domain. Transfer of this cofactor from the plant plasma membrane to the ER-localized receptors requires secured cellular transport of the reactive transition metal. In a recent study, we disclosed the transport proteins involved in the copper transfer to the receptors and identified that cytoplasmic chaperones of the ATX1-family and a membrane-bound -type ATPase are involved in copper routing. Strictly speaking, our data show that receptors can acquire their copper load by different routes and adopt the metal ion from the plasma membrane either by sequential transfer from soluble chaperones of the ATX1-family via the ER-bound copper-transporting ATPase RAN1 or by direct transfer from the soluble chaperones. Here, we have studied the properties of the soluble plant copper chaperone isoforms, ATX1 and CCH, in more detail. Our data support different cellular functions of these isoforms on copper mobilization.
植物激素乙烯是植物生命周期各个阶段生长、发育和应激适应的关键调节剂。通过位于内质网-高尔基体网络的受体激酶家族来感知和响应植物激素信号，这些受体激酶家族定位于内质网-高尔基体网络，通过结合在其跨膜结构域中的必需铜辅因子获得对化学性质简单的乙烯分子的高亲和力和特异性。将这种辅因子从植物质膜转移到内质网定位的受体需要将反应性过渡金属安全地运输到细胞内。在最近的一项研究中，我们揭示了参与向受体转移铜的转运蛋白，并确定细胞质伴侣蛋白 ATX1 家族和膜结合型 ATP 酶参与铜路由。严格来说，我们的数据表明，受体可以通过不同的途径获得其铜负载，并通过从 ATX1 家族的可溶性伴侣蛋白通过内质网结合的铜转运 ATP 酶 RAN1 顺序转移，或者直接从可溶性伴侣蛋白中获取金属离子。在这里，我们更详细地研究了可溶性植物铜伴侣蛋白同工型 ATX1 和 CCH 的性质。我们的数据支持这些同工型在铜动员方面具有不同的细胞功能。
