Human skeletal muscle fiber heterogeneity beyond myosin heavy chains (Updated September 28, 2024).

According to a preprint abstract, skeletal muscle is a diverse tissue composed of different types of muscle fibers. Traditionally, these fibers have been classified based on the expression of myosin heavy chain isoforms (MYHs). However, this study suggests that MYHs are not the sole determinants of muscle fiber heterogeneity. Through transcriptomic and proteomic analysis, the researchers found that metabolic, ribosomal, and cell junction proteins also contribute to the variation between muscle fibers. Additionally, the study found that MYH-based classifications do not accurately describe the phenotype of muscle fibers in nemaline myopathy, a genetic muscle disease. The researchers also identified novel features of slow and fast muscle fibers, including microproteins encoded by non-coding RNA transcripts. Overall, this research highlights the multi-dimensional nature of skeletal muscle fiber heterogeneity beyond MYHs. [Extracted from the article]