Component of the FTS/Hook/FHIP complex (FHF complex) (PubMed:32073997). The FHF complex may function to promote vesicle trafficking and/or fusion via the homotypic vesicular protein sorting complex (the HOPS complex). Regulates apoptosis by enhancing phosphorylation and activation of AKT1. Increases release of TNFSF6 via the AKT1/GSK3B/NFATC1 signaling cascade. FHF complex promotes the distribution of AP-4 complex to the perinuclear area of the cell (PubMed:32073997). Component of the FTS/Hook/FHIP complex (FHF complex), composed of AKTIP/FTS, FHIP1B, and one or more members of the Hook family of proteins HOOK1, HOOK2, and HOOK3. Interacts directly with HOOK1, HOOK2 and HOOK3 (PubMed:18799622, PubMed:32073997). The FHF complex associates with the homotypic vesicular sorting complex (the HOPS complex) (PubMed:18799622). Also interacts with AKT1. May interact with FHIP1A (PubMed:32073997). Belongs to the ubiquitin-conjugating enzyme family. FTS subfamily. Lacks the conserved Cys residue necessary for ubiquitin-conjugating enzyme E2 activity.