Enables mRNA binding activity. Acts upstream of or within protein localization to axon and protein localization to cell leading edge. Located in COPI-coated vesicle; Golgi apparatus; and growth cone. Is expressed in several structures, including brain; jaw bone; and thoracic segment skeleton. Orthologous to human COPA (COPI coat complex subunit alpha). [provided by Alliance of Genome Resources, Apr 2022]