AUTHOR=Wang Huan , Li Busu , Li Jiefeng , Jiang Chen , Liu Shufang , Zhuang Zhimeng 

TITLE=Label-Free Quantitative Proteomic Analysis Provides Insight Into the Differences Between Slow-Twitch Muscle and Fast-Twitch Muscle of Pseudocaranx dentex

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.842172

DOI=10.3389/fmars.2022.842172

ISSN=2296-7745

ABSTRACT=Fish skeletal muscles are mainly composed of two distinct types, fast-twitch and slow-twitch muscles, and they play important roles in maintaining movement and energy metabolism. The fast-twitch muscle contracts quickly for burst swimming, whereas the slow-twitch muscle fatigue resistance for endurance swimming. To assess the differences in molecular composition and investigate the potential regulatory mechanisms, we performed an integrative study at both proteomic and transcriptomic levels of the fast-twitch and slow-twitch muscles in Pseudocaranx dentex, a pelagic migratory fish with distinctly differentiated skeletal muscle. Label-free proteomics revealed 471 differentially expressed proteins (DEPs), 422 upregulated and 49 downregulated in slow-twitch muscle compared to fast-twitch muscle. These DEPs were mainly involved in myofibrillary structure and energy metabolism. Integrative analysis of proteomic and transcriptomic data showed that 757 RNA-protein pairs were positively correlated, and 191 were negatively correlated in abundance. Meanwhile, 311 RNA-protein pairs were consistent in both RNA and protein fold changes, and 594 exhibit striking differences, which provided an insight into the complex regulation at both transcriptional and post-transcriptional levels that contribute to shaping the different muscle types. The specific expression of multiple myofibrillar proteins, such as myosin, actin, troponin, and tropomyosin, suggested that the distinction in contraction characterizations between slow-twitch and fast-twitch muscles is related to different protein isoforms. Muscle-type specific expression of genes encoding key enzymes in fatty acid metabolism, glycolysis, TCA cycle, and oxidative phosphorylation pathways, such as CPT2, Pfkm, Pkmb, CS, IDH, and Ogdh, may be the molecular basis responsible for the differences in energy metabolism. Overall, this global view of protein and RNA expression levels in P. dentex fast-twitch and slow-twitch muscles reveals the essential roles of transcriptional and post-transcriptional regulation in maintaining muscle structure and function. The identified potential genes that may cause the differences in physiological characteristics will greatly improve our understanding on the molecular basis of skeletal muscle contraction, metabolism, and regulation in teleost.