Acts in an adapter protein-like fashion to mediate the interaction between the kinase PRKCZ and its substrate VAMP2 and increases the PRKCZ-dependent phosphorylation of VAMP2 (By similarity). Positively regulates adipocyte differentiation, by facilitating the phosphorylation and thus inactivation of the anti-adipogenetic transcription factor FOXO1 by the kinase AKT1 (PubMed:18388859). Plays a role in endosomal control of AKT2 signaling; required for insulin-stimulated AKT2 phosphorylation and glucose uptake and insulin-stimulated phosphorylation of AKT2 substrates (PubMed:20189988). Participates in transferrin receptor endocytosis (By similarity). Homodimer (By similarity). Interacts (via WD repeats 1-3) with AKT1, AKT2, PRKCZ and PRKCI (PubMed:16792529, PubMed:20189988). Interacts with VAMP2 (PubMed:17313651). Forms a complex with VAMP2 and PRKCZ (PubMed:17313651). Interacts with FOXO1 (PubMed:18388859). Forms a complex with AKT1 and FOXO1 (PubMed:18388859). Localizes to intracellular vesicles. Colocalizes with VAMP2 and PRKCZ in intracellular vesicles (By similarity). Colocalizes with AKT2 in early endosomes (PubMed:20189988). Highly expressed in the brain (at protein level). Transiently up-regulated during adipogenesis (at protein level). The FYVE-type zinc finger is essential for its vesicular localization.