Probably serves as a target for the spiC protein from Salmonella typhimurium, which inactivates it, leading to a strong alteration in cellular trafficking (By similarity). Component of the FTS/Hook/FHIP complex (FHF complex). The FHF complex may function to promote vesicle trafficking and/or fusion via the homotypic vesicular protein sorting complex (the HOPS complex). May regulate clearance of endocytosed receptors such as MSR1. Participates in defining the architecture and localization of the Golgi complex. Acts as an adapter protein linking the dynein motor complex to various cargos and converts dynein from a non-processive to a highly processive motor in the presence of dynactin. Facilitates the interaction between dynein and dynactin and activates dynein processivity (the ability to move along a microtubule for a long distance without falling off the track) (By similarity). FHF complex promotes the distribution of AP-4 complex to the perinuclear area of the cell (By similarity). (Microbial infection) Serves as a target for the spiC protein from Salmonella typhimurium, which inactivates it, leading to a strong alteration in cellular trafficking. Self-associates. 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. May interact directly with AKTIP/FTS, HOOK1 and HOOK2 (By similarity). Associates with several subunits of the homotypic vesicular sorting complex (the HOPS complex) including VPS16 and VPS41; these interactions may be indirect. Interacts with MSR1, and this association is stimulated by ligand binding to MSR1. Interacts with microtubules. Interacts with dynein intermediate chain and dynactin (DCTN1) (By similarity). Interacts with CCDC181 (By similarity). Interacts with LRGUK (By similarity). (Microbial infection) Interacts with Salmonella typhimurium spiC. Enriched at the cis-face of the Golgi complex. Localizes to microtubule asters in prophase (By similarity). Localizes to the manchette in elongating spermatids (By similarity). Belongs to the hook family.