Characterization and tissue expression analysis of mitochondrial creatine kinases (types I and II) from Pelodiscus sinensis

Abstract

The aim of this study was to characterize the functions of the mitochondrial creatine kinases in the Chinese soft-shelled turtle Pelodiscus sinensis (PSCK-MT1 and PSCK-MT2) to characterize function in relation to hibernation. Computational prediction via molecular dynamics simulations showed that PSCK-MT1 had stronger kinase- and creatine-binding affinity than PSCK-MT2. We measured PSCK-MT1 and PSCK-MT2 levels in the myocardium, liver, spleen, lung, kidney, and ovary of P. sinensis before and after hibernation and found that the expression of these enzymes was the most significantly upregulated in the ovary. We enumerated the ovarian follicles and evaluated the physiological indices of P. sinensis and discovered that fat was the main form of energy storage in P. sinensis. Moreover, both PSCK-MTs promoted follicular development during hibernation. Immunohistochemistry was used to study follicular development and revealed that both PSCK-MTs were expressed primarily in the follicular fluid and granulosa layer before and after hibernation. We found that PSCK-MT1 and PSCK-MT2 could play important roles in ovarian follicular development under hibernation. Hence, both PSCK-MTs probably function effectively under the conditions of low temperature and oxygen during hibernation.

Communicated by Ramaswamy H. Sarma

Keywords:

• mitochondrial creatine kinases
• hibernation
• Pelodiscus sinensis
• molecular dynamics
• tissue expression

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by National Natural Science Foundation of China (31402278), the Zhejiang Province Welfare Technology Applied Research Project (LGN21C190013; LGN22C190022), Zhejiang Provincial Project of Selective Breeding of Aquatic New Varieties (2021C02069-8), and Key Technology Research and Development Projects in Ningbo (2021Z009). Jinhyuk Lee was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2020R1I1A2071859) and the Korea Research Institute of Bioscience and Biotechnology (KRIBB) Research Initiative Program (KGM5362111).