Surviving winter on the Qinghai-Xizang Plateau: Extensive reversible protein phosphorylation plays a dominant role in regulating hypometabolism in hibernating <i>Nanorana parkeri</i>
Yonggang Niu, 德州学院生命科学学院, 山东 德州 253023, 中国, Dengbang Wei, Xuejing Zhang, Tisen Xu, Xiangyong Li, Haiying Zhang, Zhi-Fang An, Kenneth B. Storey, Qiang Chen, 青海大学省部共建三江源生态与高原农牧业国家重点实验室, 青海 西宁 810016, 中国, 兰州大学生命科学学院, 甘肃 兰州 730000, 中国, 卡尔顿大学生物学系, 渥太华 ON K1S 5B6, 加拿大
Abstract
Changes in protein abundance and reversible protein phosphorylation (RPP) play important roles in regulating hypometabolism but have never been documented in overwintering frogs at high altitudes. To test the hypothesis that protein abundance and phosphorylation change in response to winter hibernation, we conducted a comprehensive and quantitative proteomic and phosphoproteomic analysis of the liver of the Xizang plateau frog, <i>Nanorana parkeri</i>, living on the Qinghai-Xizang Plateau. In total, 5170 proteins and 5695 phosphorylation sites in 1938 proteins were quantified. Based on proteomic analysis, 674 differentially expressed proteins (438 up-regulated, 236 down-regulated) were screened in hibernating <i>N. parkeri</i> versus summer individuals. Functional enrichment analysis revealed that higher expressed proteins in winter were significantly enriched in immune-related signaling pathways, whereas lower expressed proteins were mainly involved in metabolic processes. A total of 4251 modified sites (4147 up-regulated, 104 down-regulated) belonging to 1638 phosphoproteins (1555 up-regulated, 83 down-regulated) were significantly changed in the liver. During hibernation, RPP regulated a diverse array of proteins involved in multiple functions, including metabolic enzymatic activity, ion transport, protein turnover, signal transduction, and alternative splicing. These changes contribute to enhancing protection, suppressing energy-consuming processes, and inducing metabolic depression. Moreover, the activities of phosphofructokinase, glutamate dehydrogenase, and ATPase were all significantly lower in winter compared to summer. In conclusion, our results support the hypothesis and demonstrate the importance of RPP as a regulatory mechanism when animals transition into a hypometabolic state.