To analyze OTX2 function in adult choroid plexus, we performed several OTX2 co-immunoprecipitation (co-IP) experiments with mass spectrometry analysis to identify potential protein partners. We previously discovered that OTX2 protein also accumulates non-cell autonomously in subventricular zone (SVZ) and rostral migratory stream (RMS) astrocytes and in visual cortex (VCx) parvalbumin cells. The identification of alternate protein partners in cell-autonomous and non-cell-autonomous contexts would suggest OTX2 takes on specific roles after transferring between cells. In order to test this hypothesis, and to reinforce choroid plexus analysis, we also performed OTX2 co-IP on lysates from adult mouse SVZ, RMS and VCx.