Synapses are characterized by highly concentrated neurotransmitter receptors in the postsynaptic membrane. The formation of neuromuscular junction (NMJ) and the clustering of nAChR (nicotinic acetylcholine receptor) at NMJ had been studied extensively. Although it is already known that MuSK acts as an essential component of agrin receptor complex and is required for nAChR clustering at the NMJ, the underlying molecular mechanisms remain unclear. In present study, we devoted our effort to identifying possible signaling pathway involving in AChR clustering by studying MuSK interacting proteins in muscle cells.We report here that using MuSK intracellular domain as bait, we pulled out Dishevelled (Dvl), a signaling molecule important for cell polarity, as MuSK interacting protein in yeast two hybrid assay. MuSK interacts with Dvl in muscle cells directly and specifically. The tempo and spatial expression profiles of MuSK and Dvl are similar in muscle. Disruption of the MuSK-Dvl interaction inhibits Agrin-induced and neuron-induced AChR clustering. Expression of dominant negative Dvll in the postsynaptic muscle cells reduces the amplitude of spontaneous synaptic currents at the NMJ.Moreover, Dvll interacts with a downstream kinase P21~activated-kinasel (PAK1), MuSK, Dvl and PAK1 form complex among them. Agrin activates PAK1, and the activation of PAK1 by agrin requires Dvl. Inhibition of PAK1 activity attenuates AChR clustering.These results demonstrate the important roles of Dvl and PAK in Agrin/MuSK induced AChR clustering, and reveal a novel function of Dvl in synapse development.