In the context of intrabodies development for the synaptic protein PSD-95, we use proteomic approaches to evaluate the possible impact of one of our evolved PSD-95 binders on the endogenous PSD-95 function. More precisely, we compare the interactome of PSD-95 in presence or absence of the Xph20 binder in primary rat neuron culture infected with the Xph20-derived probe or a control protein, EGFP.