Miaomiao Xu, Xiaoguang Liu
Maintenance of skeletal muscle mass is essential for mobility, metabolic homeostasis, and clinical outcomes across a wide spectrum of physiological and pathological conditions. While muscle atrophy and hypertrophy have traditionally been interpreted through upstream anabolic-catabolic signaling and proteolytic pathways, accumulating evidence indicates that ribosome biogenesis and translational control represent rate-limiting determinants of muscle plasticity. However, this regulatory layer remains insufficiently integrated into current models of muscle adaptation and disease. In this review, we synthesize recent advances in ribosomal RNA transcription, ribosomal protein dynamics, and translational regulation in skeletal muscle, with particular emphasis on signaling networks governed by mTORC1, c-Myc, AMPK, and FOXO. We highlight ribosome biogenesis as a central hub linking mechanical loading, nutrient availability, inflammatory stress, and metabolic status to protein synthesis capacity. Evidence from human and animal studies demonstrates that impaired ribosome production and translational efficiency precede and predict muscle atrophy in disuse, aging, cancer cachexia, and chronic disease, whereas ribosome expansion is a prerequisite for sustained hypertrophy. Beyond quantitative regulation, we discuss the emerging concept of ribosome heterogeneity as a qualitative layer of translational control that may enable selective mRNA translation during muscle growth, stress adaptation, and degeneration. We further examine ribosome-mitochondria crosstalk as a critical but underexplored mechanism coordinating anabolic capacity with cellular energetics. Finally, we outline therapeutic implications, highlighting exercise, nutritional strategies, and indirect pharmacological interventions that preserve ribosomal competence, and propose ribosome-based biomarkers as promising tools for precision management of muscle-wasting disorders. Collectively, this review positions ribosome biology as a translationally relevant framework bridging molecular mechanisms with therapeutic perspectives in skeletal muscle atrophy and hypertrophy.