Pumilio2 and Staufen2 selectively balance the synaptic proteome

Cells, in particular neurons, have the capacity to adapt to environmental stimuli, a phenomenon termed cellular plasticity. The underlying processes are controlled by a network of RNA-binding proteins (RBPs). Their impact on cellular plasticity, however, is largely unknown. To address this important question, we chose Pumilio2 (Pum2) and Staufen2 (Stau2) that both regulate synaptic transmission. Importantly, even though both RBPs dynamically interact with each other in neurons, their respective impact on the transcriptome and proteome is highly selective. While Pum2 deficiency leads to reduced translation and protein expression, Stau2 depletion preferentially impacts RNA levels and increases protein abundance. Furthermore, Pum2 activates expression of key GABAergic synaptic components, e.g. the GABAA receptor scaffold protein Gephyrin. Consequently, Pum2 depletion selectively reduced the amplitude of miniature inhibitory postsynaptic currents. Together, our data demonstrate that RBPs are needed to maintain proteostasis in order to control distinct signaling pathways which critically balance synaptic transmission.