Greasing endocytosis in plants - understanding the role of S-acylation in receptor kinase function and internalisation

受体激酶是一种蛋白质，是植物在细胞外环境中感知物理信号的主要手段。这包括病原微生物和有益微生物，植物自身细胞壁的状态和各种植物激素。因此，受体激酶对于控制植物在生长过程中如何平衡资源分配至关重要，在对病原体的抗性与种子产量或营养生产力之间进行交易。考虑到它们控制和平衡植物对环境的反应的强大能力，它们受到严格的调节和控制也就不足为奇了。这种调节的一部分包括确保已经感知到信号的受体激酶在一段时间后从植物表面移除，以允许测量和分级的环境监测和竞争感知事件的整合，而不是单一的刺激事件淹没植物。这是通过一个被称为内吞作用的过程来实现的，在这个过程中，细胞外缘的蛋白质被内化和破坏。这需要一系列事件，包括用另一种称为泛素的蛋白质“标记”蛋白质。这标志着被标记蛋白的内吞作用。我们最近发现另一种受体激酶的修饰会影响内吞作用。这种修饰被称为s -酰化，包括在受体激酶感知到刺激后向其添加脂肪酸。我们发现s -酰化对于受体的正确作用和适当的内吞作用是必要的。s -酰化的缺失实际上通过未知的途径导致更快的内吞作用，从而导致信号强度差和对刺激的无效反应。在这项工作中，我们想要了解为什么s -酰化的缺失会导致更快的内吞作用，是什么决定了受体s -酰化的发生，以及不能被s -酰化的受体所采取的内化途径。这将有助于我们了解受体激酶信号是如何被调节以提供对外部环境的适当反应的。受体激酶是植物感知世界的第一线；因此，了解受体激酶的功能可能是支持育种和转基因方法的关键，以提高病原体抗性，植物生长和产量或环境或气候挑战，如干旱，洪水，高温或低温或盐度。

Receptor kinases are proteins that act as the primary means by which plants perceive physical signals in their extracellular environment. This includes pathogenic and beneficial microbes, the state of the plant's own cell wall and various plant hormones. As a result, receptor kinases are critical to controlling how plants balance resource allocation during growth, trading resistance to pathogens against seed yield or vegetative productivity. Given their powerful ability to control and balance how plants respond to their environment it is no surprise that they are very tightly regulated and controlled. Part of this regulation involves ensuring that receptor kinases that have perceived a signal are removed from the plant surface after a period of time to allow for measured and graded environmental monitoring and integration of competing perception events, rather than a single stimulation event overwhelming the plant. This is achieved through a process known as endocytosis whereby proteins on the outer edge of the cell are internalised and destroyed. This requires a number of events including the "tagging" of the proteins with another protein known as ubiquitin. This marks the tagged protein for endocytosis. We recently discovered that another modification of receptor kinases affects endocytosis. This modification, known as S-acylation, involves adding fatty acids to receptor kinases once they have perceived a stimulus. We found that S-acylation is essential for correct action by a receptor and is necessary for appropriate endocytosis. Loss of S-acylation actually causes more rapid endocytosis through an unknown route and, as a result, leads to poor signal strength and ineffective response to the stimulus. In this work we want to understand why loss of S-acylation causes more rapid endocytosis, what dictates that receptor S-acylation will occur and the route of internalisation taken by receptors that can't be S-acylated. This will help us to understand how receptor kinase signalling is regulated to deliver appropriate responses to the external environment. Receptor kinases are the frontline of how plants perceive their world; understanding how receptor kinases function could therefore be key towards supporting breeding and transgenic approaches to improve pathogen resistance, plant growth and yield or environmental or climate challenge such as drought, flooding, high or low temperature or salinity.