We carried out 4 HDX-MS experiments to investigate the ARMH3 interactions with PI4Kb, Arl5b(GTPyS) and GBF1 (ARMH3+Arl5b, ARMH3+GBF1(1-709)) and ARMH3+GBF1(364-395)). Analysis of these four experiments defined the Arl5b intereface on ARMH3 and defined the disordered linker region located in the DCB-HUS domains region of GBF1 (residues 364-395) as the ARMH3 binding region (ABR)