MUSK (muscle-associated receptor tyrosine kinase) is a transmembrane receptor tyrosine kinase essential for neuromuscular junction (NMJ) formation and maintenance 1. MUSK functions as the catalytic component of a signaling complex where recruitment of agrin by LRP4 induces MUSK phosphorylation and activation 1. Activated MUSK regulates NMJ development through multiple mechanisms: acetylcholine receptor (AChR) clustering at the postsynaptic membrane, reorganization of the actin cytoskeleton, and subsynaptic gene expression 1. MUSK coordinates these processes by activating downstream effectors including Src family kinases and Rho GTPases 1. Clinically, MUSK is a major autoantigen in myasthenia gravis (MG), an autoimmune disease affecting neuromuscular transmission 23. Anti-MuSK antibodies, predominantly IgG4 subclass, account for 6% of MG cases and cause distinct immunopathology compared to AChR-antibody MG 45. MuSK-MG presents with predominant bulbar and focal muscle involvement, affecting women with early-onset disease 6. Importantly, MUSK is also mutated in congenital myasthenic syndrome 7. Recent therapeutic advances include rituximab for anti-MuSK MG, achieving remission in 56% of patients 8, and ARGX-119, a MUSK agonist antibody that restores neuromuscular function in experimental models 7.