Acts as a non-receptor guanine nucleotide exchange factor which binds to and activates G-protein alpha subunit goa-1. Interacts (via GBA motif) with guanine nucleotide-binding protein G(o) subunit alpha goa-1 (in GDP-bound form); the interaction leads to activation of goa-1. Expressed in some neurons including the head and tail neurons, HSN and VC, in a subset of glial cells, in the distal tips cells and in the intestine. The GBA (G-alpha binding and activating) motif mediates binding to the alpha subunits of guanine nucleotide-binding proteins (G proteins).