Probable muscle-intrinsic activator of MUSK that plays an essential role in neuromuscular synaptogenesis. Acts in aneural activation of MUSK and subsequent acetylcholine receptor (AchR) clustering in myotubes. Induces autophosphorylation of MUSK.
Subcellular locations: Cell membrane, Synapse
Accumulates at neuromuscular junctions.
Preferentially expressed in skeletal muscle and heart. Present in thigh muscle, diaphragm and heart but not in the liver or spleen (at protein level).