Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
Nat Commun. 2022 Dec 8;13(1):7588. doi: 10.1038/s41467-022-35298-y.
The eukaryotic proteome undergoes constant surveillance by quality control systems that either sequester, refold, or eliminate aberrant proteins by ubiquitin-dependent mechanisms. Ubiquitin-conjugation necessitates the recognition of degradation determinants, termed degrons, by their cognate E3 ubiquitin-protein ligases. To learn about the distinctive properties of quality control degrons, we performed an unbiased peptidome stability screen in yeast. The search identify a large cohort of proteome-derived degrons, some of which exhibited broad E3 ligase specificity. Consequent application of a machine-learning algorithm establishes constraints governing degron potency, including the amino acid composition and secondary structure propensities. According to the set criteria, degrons with transmembrane domain-like characteristics are the most probable sequences to act as degrons. Similar quality control degrons are present in viral and human proteins, suggesting conserved degradation mechanisms. Altogether, the emerging data indicate that transmembrane domain-like degron features have been preserved in evolution as key quality control determinants of protein half-life.
真核生物蛋白质组受到质量控制系统的持续监控,这些系统通过泛素依赖的机制将异常蛋白质隔离、重折叠或消除。泛素缀合需要其同源 E3 泛素蛋白连接酶识别降解决定因素,称为降解靶标。为了了解质量控制降解靶标的独特特性,我们在酵母中进行了一项无偏的肽组稳定性筛选。该研究发现了一大群由蛋白质组衍生的降解靶标,其中一些靶标表现出广泛的 E3 连接酶特异性。随后应用机器学习算法确定了控制降解靶标效力的约束条件,包括氨基酸组成和二级结构倾向。根据设定的标准,具有跨膜结构域样特征的降解靶标最有可能作为降解靶标发挥作用。在病毒和人类蛋白中也存在类似的质量控制降解靶标,表明存在保守的降解机制。总之,这些新出现的数据表明,跨膜结构域样降解靶标特征在进化中得到了保留,是蛋白质半衰期的关键质量控制决定因素。