S-acylation is the addition of a fatty acid to a cysteine residue of a protein. While this modification may profoundly alter protein behaviour, its effects on the function of plant proteins remains poorly characterized, largely as a result of the lack of basic information regarding which proteins are S-acylated and where in the proteins the modification occurs. To address this gap in our knowledge, we used an optimized acyl-resin-assisted capture assay to perform a comprehensive analysis of plant protein S-acylation from six separate tissues. In our high- and medium-confidence groups, we identified 1,849 cysteines modified by S-acylation, which were located in 1,640 unique peptides from 1,094 different proteins. This represents around 6% of the detectable Arabidopsis proteome and suggests an important role for S-acylation in many essential cellular functions including trafficking, signalling and metabolism. To illustrate the potential of this dataset, we focus on cellulose synthesis and confirm the S-acylation of a number of proteins known to be involved in cellulose synthesis and trafficking of the cellulose synthase complex. In the secondary cell walls, cellulose synthesis requires three different catalytic subunits (CESA4, CESA7 and CESA8) that all exhibit striking sequence similarity and are all predicted to possess a RING-type zinc finger at their amino terminus composed of eight cysteines. For CESA8, we find evidence for S-acylation of these cysteines that is incompatible with any role in coordinating metal ions. We show that while CESA7 may possess a RING-type domain, the same region of CESA8 appears to have evolved a very different structure. Together, the data suggest that this study represents an atlas of S-acylation in Arabidopsis that will facilitate the broader study of this elusive post-translational modification in plants as well as demonstrating the importance of further work in this area.

S-酰化是将脂肪酸添加到蛋白质的半胱氨酸残基上。虽然这种修饰可能会深刻地改变蛋白质的行为，但它对植物蛋白功能的影响仍然很差，这主要是由于缺乏关于哪些蛋白质被 S-酰化以及在蛋白质中发生修饰的位置的基本信息。为了解决我们知识上的这一差距，我们使用优化的酰基树脂辅助捕获测定对来自六个不同组织的植物蛋白 S-酰化进行全面分析。在我们的高置信度和中等置信度组中，我们鉴定了 1,849 个经 S-酰化修饰的半胱氨酸，它们位于来自 1,094 种不同蛋白质的 1,640 个独特肽段中。这约占可检测拟南芥的 6%蛋白质组学，并表明 S-酰化在包括运输、信号传导和代谢在内的许多基本细胞功能中的重要作用。为了说明该数据集的潜力，我们专注于纤维素合成并确认已知参与纤维素合成和纤维素合酶复合物运输的许多蛋白质的 S-酰化。在次生细胞壁中，纤维素合成需要三个不同的催化亚基（CESA4、CESA7 和 CESA8），它们都表现出惊人的序列相似性，并且都预测在其氨基末端具有由八个半胱氨酸组成的环型锌指。对于 CESA8，我们发现这些半胱氨酸 S-酰化的证据与配位金属离子的任何作用都不相容。我们表明，虽然 CESA7 可能具有 RING 型域，CESA8 的同一区域似乎已经进化出非常不同的结构。总之，数据表明这项研究代表了 S-酰化的图谱拟南芥将有助于对植物中这种难以捉摸的翻译后修饰进行更广泛的研究，并证明在该领域进一步工作的重要性。