Division of Plant Science, School of Life Science, University of Dundee (at JHI), Invergowrie, Dundee, DD2 5DA, UK.
Cell and Molecular Sciences, James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK.
Sci Rep. 2019 Sep 6;9(1):12818. doi: 10.1038/s41598-019-49302-x.
S-acylation is a common post-translational modification of membrane protein cysteine residues with many regulatory roles. S-acylation adjacent to transmembrane domains has been described in the literature as affecting diverse protein properties including turnover, trafficking and microdomain partitioning. However, all of these data are derived from mammalian and yeast systems. Here we examine the role of S-acylation adjacent to the transmembrane domain of the plant pathogen perceiving receptor-like kinase FLS2. Surprisingly, S-acylation of FLS2 adjacent to the transmembrane domain is not required for either FLS2 trafficking or signalling function. Expanding this analysis to the wider plant receptor-like kinase family we find that S-acylation adjacent to receptor-like kinase domains is common, affecting ~25% of Arabidopsis receptor-like kinases, but poorly conserved between orthologues through evolution. This suggests that S-acylation of receptor-like kinases at this site is likely the result of chance mutation leading to cysteine occurrence. As transmembrane domains followed by cysteine residues are common motifs for S-acylation to occur, and many S-acyl transferases appear to have lax substrate specificity, we propose that many receptor-like kinases are fortuitously S-acylated once chance mutation has introduced a cysteine at this site. Interestingly some receptor-like kinases show conservation of S-acylation sites between orthologues suggesting that S-acylation has come to play a role and has been positively selected for during evolution. The most notable example of this is in the ERECTA-like family where S-acylation of ERECTA adjacent to the transmembrane domain occurs in all ERECTA orthologues but not in the parental ERECTA-like clade. This suggests that ERECTA S-acylation occurred when ERECTA emerged during the evolution of angiosperms and may have contributed to the neo-functionalisation of ERECTA from ERECTA-like proteins.
S-酰化是一种常见的翻译后修饰，发生在膜蛋白半胱氨酸残基上，具有许多调节作用。文献中描述了跨膜结构域附近的 S-酰化，它可以影响多种蛋白质的性质，包括周转率、运输和微区分配。然而，所有这些数据都来自哺乳动物和酵母系统。在这里，我们研究了植物病原体感知受体样激酶 FLS2 跨膜结构域附近的 S-酰化的作用。令人惊讶的是，FLS2 跨膜结构域附近的 S-酰化对于 FLS2 的运输或信号转导功能都不是必需的。将这一分析扩展到更广泛的植物受体样激酶家族，我们发现受体样激酶结构域附近的 S-酰化是常见的，影响了约 25%的拟南芥受体样激酶，但在进化过程中同源物之间的保守性很差。这表明，该位点受体样激酶的 S-酰化很可能是随机突变导致半胱氨酸出现的结果。由于跨膜结构域后面紧接着是半胱氨酸残基，这是 S-酰化发生的常见模体，并且许多 S-酰基转移酶似乎具有宽松的底物特异性，因此我们提出，许多受体样激酶偶然地被 S-酰化，一旦该位点发生随机突变引入了半胱氨酸。有趣的是，一些受体样激酶在同源物之间显示出 S-酰化位点的保守性，这表明 S-酰化已经开始发挥作用，并在进化过程中被正向选择。最显著的例子是在 ERECTA 样家族中，跨膜结构域附近的 ERECTA 的 S-酰化发生在所有 ERECTA 同源物中，但不在母体 ERECTA 样分支中。这表明，当 ERECTA 在被子植物进化过程中出现时，发生了 ERECTA 的 S-酰化，并且可能有助于 ERECTA 从 ERECTA 样蛋白的新功能化。
