The Arabidopsis has 51 proteins annotated as serine carboxypeptidase-like (SCPL) enzymes. Although biochemical and cellular characterization indicates SCPLs involved in protein turnover or processing, little is known about their roles in plant metabolism. In this study, we identified an Arabidopsis mutant, bis4 (1-butanol insensitive 4), that was insensitive to the inhibitory effect of 1-butanol on seed germination. We cloned the gene that was defective in bis4 and found that it encoded an SCPL41 protein. Transgenic Arabidopsis plants constitutively expressing SCPL41 were generated, oil body staining and lipidomic assays indicated that SCPL41-overexpressing plants showed a decrease in membrane lipid content, especially digalactosyl diglyceride (DGDG) and monogalactosyl diglyceride (MGDG) contents, while the loss of SCPL41 increased the membrane lipid levels compared with those in wild-type plants. These findings suggested that SCPL41 had acquired novel functions in membrane lipid metabolism.

中文翻译：

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丝氨酸羧肽酶样基因SCPL41负调节拟南芥中的膜脂代谢。

在拟南芥有51种蛋白注释为丝氨酸羧肽酶样（SCPL）的酶。尽管生化和细胞特征表明SCPL参与蛋白质更新或加工，但对其在植物代谢中的作用知之甚少。在这项研究中，我们确定了一个拟南芥突变体bis4（1-丁醇不敏感4），它对1-丁醇对种子发芽的抑制作用不敏感。我们克隆了在bis4中有缺陷的基因，发现该基因编码SCPL41蛋白。产生了组成型表达SCPL41的转基因拟南芥植物，油体染色和脂质组分析表明SCPL41过表达植物显示出膜脂质含量降低，尤其是二半乳糖基甘油二酸酯（DGDG）和单半乳糖基甘油二酸酯（MG​​DG）含量降低，而SCPL41的损失与野生型植物相比增加了膜脂质水平。这些发现表明SCPL41在膜脂质代谢中获得了新的功能。