WWC1/2 regulate spinogenesis and cognition in mice by stabilizing AMOT.

WWC1 regulates episodic learning and memory, and genetic nucleotide polymorphism of WWC1 is associated with neurodegenerative diseases such as Alzheimer's disease. However, the molecular mechanism through which WWC1 regulates neuronal function has not been fully elucidated. Here, we show that WWC1 and its paralogs (WWC2/3) bind directly to angiomotin (AMOT) family proteins (Motins), and recruit USP9X to deubiquitinate and stabilize Motins. Deletion of WWC genes in different cell types leads to reduced protein levels of Motins. In mice, neuron-specific deletion of Wwc1 and Wwc2 results in reduced expression of Motins and lower density of dendritic spines in the cortex and hippocampus, in association with impaired cognitive functions such as memory and learning. Interestingly, ectopic expression of AMOT partially rescues the neuronal phenotypes associated with Wwc1/2 deletion. Thus, WWC proteins modulate spinogenesis and cognition, at least in part, by regulating the protein stability of Motins.