Acetylation is an important, reversible posttranslational modification to a protein. In a previous study, we found that there were a large number of acetylated sites in various nutrient storage proteins of the silkworm haemolymph. In this study, we confirmed that acetylation can affect the stability of nutrient storage protein Bombyx mori apolipophorin‐III (BmApoLp‐III). First, the expression of BmApoLp‐III could be upregulated when BmN cells were treated with the deacetylase inhibitor panobinostat (LBH589); similarly, the expression was downregulated when the cells were treated with the acetylase inhibitor C646. Furthermore, the increase in acetylation by LBH589 could inhibit the degradation and improve the accumulation of BmApoLp‐III in BmN cells treated with cycloheximide and MG132 respectively. Moreover, we found that an increase in acetylation could decrease the ubiquitination of BmApoLp‐III and vice versa; therefore, we predicted that acetylation could improve the stability of BmApoLp‐III by competing for ubiquitination and inhibiting the protein degradation pathway mediated by ubiquitin. Additionally, BmApoLp‐III had an antiapoptosis function that increased after LBH589 treatment, which might have been due to the improved protein stability after acetylation. These results have laid the foundation for further study on the mechanism of acetylation in regulating the storage and utilization of silkworm nutrition.

中文翻译：

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乙酰化对家蚕BmApoLp-III蛋白质稳定性的影响。

乙酰化是蛋白质的重要​​的，可逆的翻译后修饰。在先前的研究中，我们发现家蚕血淋巴的各种营养物存储蛋白中存在大量乙酰化位点。在这项研究中，我们证实了乙酰化可以影响营养存储蛋白Bombyx mori的稳定性。载脂蛋白III（BmApoLp-III）。首先，当用脱乙酰基酶抑制剂panobinostat（LBH589）处理BmN细胞时，BmApoLp-III的表达可能被上调；类似地，当用乙酰酶抑制剂C646处理细胞时，表达下调。此外，LBH589增强乙酰化作用可以抑制降解，并改善分别用环己酰亚胺和MG132处理的BmN细胞中BmApoLp-III的积累。此外，我们发现乙酰化作用的增加可能会降低BmApoLp-III的泛素化，反之亦然；因此，我们预测乙酰化可以通过竞争泛素化和抑制泛素介导的蛋白质降解途径来提高BmApoLp-III的稳定性。另外，BmApoLp-III的抗凋亡功能在LBH589处理后增加，这可能是由于乙酰化后蛋白质稳定性的提高。这些结果为进一步研究乙酰化调控家蚕营养贮藏利用的机理奠定了基础。