MuSK is a central regulator of neuromuscular synapse formation. It belongs to the family of receptor tyrosine kinases and its kinase activity is essential for postsynaptic differentiation.
Posttranslational modifications greatly regulate the activity and functions of proteins. Phosphorylation is the best-known form of posttranslational modification. MuSK activity is critically regulated by phosphorylation: blocked phosphorylation inhibits MuSK activation and downstream signaling. We have used a quantitative phosphoproteomics screen to identify phosphotargets of MuSK signaling. We have been able to show that transcriptional as well as cytoskeletal protein networks are activated. We have been analyzing proteins within these networks as well as novel MuSK phosphorylation events to better understand the complex interplay between molecular and cellular determinants of neuromuscular junction development.