Raw mass spec. data files, converted peak lists and TPP results files for KCMF1 links RAD6 to UBR4 and lysosome-mediated degradation by Hong et. al, MCP 2014. RAD6 is a ubiquitin E2 protein with roles in a number of different biological processes. Here, using affinity purification coupled with mass spectrometry, we identify a number of new RAD6 binding partners, including the E3 ligase KCMF1 (potassium channel modulatory factor 1). NMR, combined with in vivo and in vitro interaction mapping, demonstrate that the KCMF1 C-terminus binds directly to RAD6, while the N-terminus interacts with vesicle- and mitochondria-associated proteins. KCMF1 and RAD6 co-localize at late endosomes and lysosomes, and cells disrupted for KCMF1 or RAD6 function display defects in vesicle dynamics. Notably, we also find that RAD6A point mutants (R7W and R11Q) found in X-linked intellectual disability (XLID) patients specifically lose the interaction with KCMF1, but not with other previously identified RAD6 interactors. We thus identify a new set of RAD6 interacting partners linked to lysosome-mediated degradation, and highlight specific protein-protein interactions that are lost in some RAD6 XLID mutant proteins.