May be involved in cytoskeletal organization and tumorogenicity. Seems to be involved in a signaling transduction pathway leading to activation of MAPK1/ERK2. Plays a role in EGFR trafficking from recycling endosomes back to the cell membrane (PubMed:29030480). Guanine nucleotide exchange factor (GEF) which may activate RAB9A and RAB9B. Promotes the exchange of GDP to GTP, converting inactive GDP-bound Rab proteins into their active GTP-bound form. May block ERK2 activation stimulated by ABL1 (Probable). May alter cell morphology and cell growth (Probable). Interacts with ITSN1 and GRB2 (PubMed:29030480). Isoform 1 interacts with the SH3 domain of ABL1. Colocalizes with RAB13 and ITSN1 at cytoplasmic vesicles that are most likely recycling endosomes. Colocalizes with the cortical actin cytoskeleton. Widely expressed with the exception of peripheral blood lymphocytes. Isoform 1 is expressed in several epithelial and fibroblast (including tumorigenic) but absent in lymphoid cell lines (at protein level). Isoform 3 is expressed in primary cell or weakly tumorigenic but not in tumorigenic cell lines (at protein level). Phosphorylated. Phosphorylation decreases ITSN1 binding. Produced by alternative promoter usage. Produced by alternative splicing of isoform 1. Produced by alternative promoter usage.