Phosphoproteomics of MuSK Signaling

The development of the neuromuscular synapse depends on signaling processes which involve protein phosphorylation as a crucial regulatory event. The receptor tyrosine kinase MuSK is the key signaling molecule at the neuromuscular synapse whose activity is required for the formation of a mature and functional neuromuscular synapse. However, the signaling cascade downstream of MuSK and the regulation of the different components is still poorly understood. Here we present data from a quantitative phosphoproteomics approach to study MuSK-dependent processes. Muscle cells were stimulated with the heparansulfate proteoglycan agrin, which activates MuSK and downstream signaling events. To get an insight into the signaling dynamics we used three different time points (unstimulated, 15 min, 60 min and 4 hrs).