Enables G-protein alpha-subunit binding activity and GDP-dissociation inhibitor activity. Acts upstream of or within establishment of mitotic spindle orientation and lung epithelial cell differentiation. Located in apical part of cell and lateral cell cortex. Is expressed in several structures, including gonad; lung; nervous system; sensory organ; and spleen. Human ortholog(s) of this gene implicated in sensorineural hearing loss. Orthologous to human GPSM2 (G protein signaling modulator 2). [provided by Alliance of Genome Resources, Apr 2022]