The insertion and removal of neurotransmitter receptors is thought to contribute to plasticity at synapses; however, the signalling mechanisms underlying such receptor dynamics have not been fully elucidated. Here, the authors show that synaptic plasticity at the Caenorhabditis elegans neuromuscular junction involves the translocation of acetylcholine receptors to the cell surface. Furthermore, they reveal a crucial role for a WNT signalling pathway in regulating acetylcholine receptor expression, transmission and plasticity at this synapse.