Figure 1. Innervation triggers recruitment of neurotransmitter receptors at the NMJ. Before innervation, receptor complexes (represented by red dots) are present in nascent, small clusters scattered on the muscle fiber. After innervation, the receptor complexes form large clusters/aggregates juxtaposing the active zones on the presynaptic termini. In the absence of Neto or any essential receptor subunit, iGluRs do not form synaptic clusters even after innervation.