Componement of the CCZ1-MON1 RAB7A guanine exchange factor (GEF). Acts as a positive regulator of CCZ1-MON1A/B function necessary for endosomal/autophagic flux and efficient RAB7A localization (PubMed:29038162). Found in a complex with RMC1, CCZ1 MON1A and MON1B. Belongs to the RMC1 family.