PACS1 syndrome is a neurodevelopmental disorder caused by a recurrent heterozygous missense mutation in PACS1 (p.R203W). We previously showed that PACS1R203W aberrantly potentiates HDAC6 activity, leading to Golgi fragmentation and neuronal deficits through an unresolved mechanism. To elucidate how PACS1R203W and HDAC6 disrupt Golgi positioning, we performed a proteomic screen to identify additional PACS1R203W partners involved in microtubule-based trafficking. HCT116 cells expressing FLAG-tagged PACS1R203W or PACS1 (control) underwent anti-FLAG immunoprecipitation (IP), and the co-purified proteins were analyzed by tandem mass spectrometry (LC-MS/MS).