p140Cap is an adapter protein that is highly expressed in the brain. In particular, p140Cap localizes at dendritic spines where it contributes to the regulation of spine shape and maturation. We recently described that p140Cap knock-out mice present cognitive deficits, impaired long-term potentiation and long-term depression, and immature filopodia-like dendritic spines, indicating that p140Cap is relevant for synaptic plasticity. Although a few p140Cap interacting proteins have been identified in the brain, a comprehensive view of its molecular partners remains largely unknown. Thus, we performed a mass spectrometry-based proteomic analysis of the p140Cap interactome.