Enables GTPase inhibitor activity. Predicted to be involved in sensory perception of light stimulus. Predicted to act upstream of or within phototransduction. Predicted to be located in cytoplasmic vesicle and cytosol. Predicted to be active in cytoplasm. Is expressed in several structures, including alimentary system; genitourinary system; nervous system; respiratory system; and sensory organ. Human ortholog(s) of this gene implicated in Joubert syndrome 22. Orthologous to human PDE6D (phosphodiesterase 6D). [provided by Alliance of Genome Resources, Apr 2022]