Laboratorio de Cronobiología, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes/CONICET, Bernal B1876BXD, Argentina.
Institute for Biomedical Research (BIOMED), Catholic University of Argentina/CONICET, Buenos Aires C1107CABA, Argentina.
Biomolecules. 2022 Jun 25;12(7):892. doi: 10.3390/biom12070892.
The molecular circadian clock is based on a transcriptional/translational feedback loop in which the stability and half-life of circadian proteins is of importance. Cysteine residues of proteins are subject to several redox reactions leading to S-thiolation and disulfide bond formation, altering protein stability and function. In this work, the ability of the circadian protein period 2 (PER2) to undergo oxidation of cysteine thiols was investigated in HEK-293T cells. PER2 includes accessible cysteines susceptible to oxidation by nitroso cysteine (CysNO), altering its stability by decreasing its monomer form and subsequently increasing PER2 homodimers and multimers. These changes were reversed by treatment with 2-mercaptoethanol and partially mimicked by hydrogen peroxide. These results suggest that cysteine oxidation can prompt PER2 homodimer and multimer formation in vitro, likely by S-nitrosation and disulphide bond formation. These kinds of post-translational modifications of PER2 could be part of the redox regulation of the molecular circadian clock.
分子生物钟基于转录/翻译反馈环，其中生物钟蛋白的稳定性和半衰期很重要。蛋白质的半胱氨酸残基易受几种氧化还原反应的影响，导致 S-巯基化和二硫键形成，从而改变蛋白质的稳定性和功能。在这项工作中，研究了昼夜节律蛋白 PER2 中半胱氨酸巯基发生氧化的能力在 HEK-293T 细胞中。PER2 包含易受亚硝基半胱氨酸 (CysNO) 氧化的可及半胱氨酸，通过降低其单体形式来改变其稳定性，随后增加 PER2 同源二聚体和多聚体。这些变化可以通过 2-巯基乙醇处理逆转，并部分模仿过氧化氢。这些结果表明，半胱氨酸氧化可以在体外促使 PER2 同源二聚体和多聚体的形成，可能通过 S-亚硝化和二硫键形成。PER2 的这种翻译后修饰可能是分子生物钟氧化还原调节的一部分。
