Acts as a guanine nucleotide exchange factor (GEF) for ARF1. Interacts with DLG1 and DLG4 (PubMed:15189337). Interacts with GPHN (By similarity). Expressed in brain. Localized to dendrites, as well as somas of neuronal cells. Expressed at E18 in hippocampal neurons. Belongs to the BRAG family.