FMR1 and fragile X syndrome: Nevertheless, the GluRIIA accumulation in the Drosophila FXS model (Pan and Broadie, 2007) is well explained by the postsynaptic FMRP-Stau-Cora regulative pathway, which activates phosphorylation of presynaptic Mothers against Decapentaplegic (Mad) to drive NMJ bouton overgrowth (Figure 1; Song et al., 2022).