Selective protein degradation typically involves substrate recognition via short linear motifs known as degrons. Various degrons can be found at protein termini from bacteria to mammals. While N-degrons have been extensively studied, our understanding of C-degrons is still limited. Towards a comprehensive understanding of eukaryotic C-degron pathways, here we perform an unbiased survey of C-degrons in budding yeast. We identify over 5000 potential C-degrons by stability profiling of random peptide libraries and of the yeast C‑terminome. Combining machine learning, high-throughput mutagenesis and genetic screens reveals that the SCF ubiquitin ligase targets ~40% of degrons using a single F-box substrate receptor Das1. Although sequence-specific, Das1 is highly promiscuous, recognizing a variety of C-degron motifs. By screening for full-length substrates, we implicate SCF^Das1 in degradation of orphan protein complex subunits. Altogether, this work highlights the variety of C-degron pathways in eukaryotes and uncovers how an SCF/C-degron pathway of broad specificity contributes to proteostasis.

选择性蛋白质降解通常涉及通过称为降解决定子的短线性基序进行底物识别。从细菌到哺乳动物的蛋白质末端都可以发现各种降解决定子。虽然 N-降解决定子已被广泛研究，但我们对 C-降解决定子的了解仍然有限。为了全面了解真核 C-降解决定子途径，我们在这里对芽殖酵母中的 C-降解决定子进行了公正的调查。我们通过随机肽文库和酵母 C 末端组的稳定性分析鉴定了 5000 多个潜在的 C 降解决定子。结合机器学习、高通量诱变和遗传筛选表明，SCF 泛素连接酶使用单个 F-box 底物受体 Das1 靶向约 40% 的降解决定子。尽管具有序列特异性，但 Das1 是高度混杂的，可识别多种 C 降解决定子基序。通过筛选全长底物，我们发现 SCF ^Das1参与了孤儿蛋白复合物亚基的降解。总而言之，这项工作强调了真核生物中 C-降解决定子途径的多样性，并揭示了广泛特异性的 SCF/C-降解决定子途径如何促进蛋白质稳态。