Guanine nucleotide exchange factor (GEF), which can activate some, but not all, G-alpha proteins by exchanging bound GDP for free GTP. Able to potentiate G(olf)-alpha-dependent cAMP accumulation suggesting that it may be an important component for odorant signal transduction (Probable). Interacts with GDP-bound G alpha proteins GNAI1, GNAL, GNAS and GNAQ. Does not interact with G-alpha proteins when they are in complex with subunits beta and gamma. Localizes to the cell cortex. Belongs to the synembryn family.