<p>Neuronal development and function are orchestrated by a plethora of regulatory mechanisms that control the abundance, localization, interactions, and function of proteins. A key role in this regard is assumed by post-translational protein modifications (PTMs). While some PTM types, such as phosphorylation or ubiquitination, have been explored comprehensively, PTMs involving ubiquitin-like modifiers (Ubls) have remained comparably enigmatic (Ubls). This is particularly true for the Ubl Nedd8 and its conjugation to proteins, i.e. neddylation, in nerve cells. In the present study, we generated a conditional Nedd8 knock-out mouse line and examined the consequences of Nedd8-deletion in cultured post-mitotic glutamatergic neurons. Our findings reveal that Nedd8-ablation in young glutamatergic neurons causes alterations in the expression of developmental transcription factors that control neuronal differentiation, ultimately leading to defects in the development of a mature glutamatergic neuronal phenotype. Apparent manifestations of these defects include increased vGlut2 expression levels, reduced vGlut1 and endophilin1 expression levels, reduced dendrite complexity, and increased transmitter release probability. Collectively, our results highlight a pivotal role for neddylation in controlling the fate of glutamatergic neurons and excitatory synaptic transmission.</p>