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 (PubMed:17313651). 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 (By similarity). Participates in transferrin receptor endocytosis (PubMed:16873553). {ECO:0000250|UniProtKB:Q8BUB4, ECO:0000269|PubMed:16873553, ECO:0000269|PubMed:17313651, ECO:0000269|PubMed:18388859}. This is the function of ENSG00000139668 (WDFY2, WD repeat and FYVE domain containing 2).