Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel.
Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel.
Mol Cell Proteomics. 2023 Jul;22(7):100584. doi: 10.1016/j.mcpro.2023.100584. Epub 2023 May 24.
The N termini of proteins contain information about their biochemical properties and functions. These N termini can be processed by proteases and can undergo other co- or posttranslational modifications. We have developed LATE (LysN Amino Terminal Enrichment), a method that uses selective chemical derivatization of α-amines to isolate the N-terminal peptides, in order to improve N-terminome identification in conjunction with other enrichment strategies. We applied LATE alongside another N-terminomic method to study caspase-3-mediated proteolysis both in vitro and during apoptosis in cells. This has enabled us to identify many unreported caspase-3 cleavages, some of which cannot be identified by other methods. Moreover, we have found direct evidence that neo-N-termini generated by caspase-3 cleavage can be further modified by Nt-acetylation. Some of these neo-Nt-acetylation events occur in the early phase of the apoptotic process and may have a role in translation inhibition. This has provided a comprehensive overview of the caspase-3 degradome and has uncovered previously unrecognized cross talk between posttranslational Nt-acetylation and caspase proteolytic pathways.
蛋白质的 N 端包含有关其生化特性和功能的信息。这些 N 端可以被蛋白酶加工，并经历其他共翻译或翻译后修饰。我们开发了 LATE（赖氨酸 N 末端富集），这是一种使用α-氨基的选择性化学衍生化来分离 N 末端肽的方法，以便与其他富集策略一起改善 N 末端组学的鉴定。我们将 LATE 与另一种 N 末端组学方法一起应用于研究体外和细胞凋亡过程中 caspase-3 介导的蛋白水解。这使我们能够识别许多未报道的 caspase-3 切割，其中一些无法通过其他方法识别。此外，我们发现了直接证据表明，caspase-3 切割产生的新 N 末端可以被 Nt-乙酰化进一步修饰。其中一些新的 Nt-乙酰化事件发生在凋亡过程的早期阶段，可能在翻译抑制中起作用。这提供了 caspase-3 降解组的全面概述，并揭示了翻译后 Nt-乙酰化和 caspase 蛋白水解途径之间以前未被识别的交叉对话。
