Signaling networks governing skeletal muscle growth, atrophy, and cachexia.

Maintaining skeletal muscle mass and strength is essential for healthy aging and overall longevity. Muscle mass is governed by a complex network of signaling pathways that coordinate proteostasis and regulate the expression of anabolic and catabolic genes. Recent research has uncovered several new signaling proteins that modulate skeletal muscle mass through distinct molecular mechanisms. In this review, we summarize current understanding of the signaling cascades that control skeletal muscle mass under both physiological and pathophysiological conditions, including cancer-induced cachexia. We also discuss newly identified anabolic and catabolic factors that regulate specific intracellular pathways involved in myofiber growth and atrophy. Additionally, we highlight key knowledge gaps in the field and suggest future research directions aimed at targeting distinct signaling pathways to improve skeletal muscle mass and function in various catabolic conditions and disease states.