TMOD4 (tropomodulin 4) is an actin-capping protein that blocks elongation and depolymerization of actin filaments at the pointed end, contributing to thin filament length regulation and sarcomere assembly in muscle 1. TMOD4 is predominantly expressed in muscle tissues 1 and functions redundantly with leiomodin 3 during skeletal myofibrillogenesis; loss of either protein disrupts sarcomere assembly, though compensatory upregulation can restore function 2. Notably, TMOD1 appears to be the primary regulator of thin filament length in adult skeletal muscle, with TMOD4 being largely dispensable for this function under normal conditions 3. Beyond muscle function, TMOD4 has unexpected roles in metabolic disease. The LEPIS-HuR-TMOD4 regulatory axis controls hepatic cholesterol homeostasis by affecting PCSK9 and LDLR expression, with TMOD4 overexpression accelerating atherosclerosis in mice 4. In liver cancer, BFSP1 directly interacts with TMOD4 to promote aerobic glycolysis and tumor progression through m6A-mediated regulation 5. Genetic variants in TMOD4 are associated with susceptibility to early-onset myocardial infarction, hypertension, and chr1 kidney disease 6, suggesting TMOD4 has broader cardiovascular and metabolic significance beyond skeletal muscle physiology.