Forgetting and receptor removal The trafficking of AMPA receptors to and from the surface of postsynaptic membranes regulates synaptic strength and underlies learning and memory. Awasthi et al. found that the integral membrane protein synaptotagmin-3 (Syt3) is predominantly found on postsynaptic endocytic zones of neurons, where it promotes AMPA receptor internalization (see the Perspective by Mandelberg and Tsien). In Syt3 overexpressing or knockdown neurons, synaptic transmission and short-term plasticity were unchanged. However, in neurons from Syt3 knockout mice, synaptic long-term depression was abolished and decaying long-term potentiation endured. In Syt3 knockout mice, spatial learning was unaltered; however, these animals showed signs of impaired forgetting and relearning during the water maze spatial memory task. Science , this issue p. eaav1483 ; see also p. 31