NEDD4 and schizophrenia: Several studies have shown that abnormal expression of the NEDD4 protein in brain affects the ubiquitination of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit glutamate receptor 1 (GluR1), and the dysfunction of GluR1 may be related to the pathogenesis of schizophrenia and its cognitive dysfunction [12–14].