Enables GTPase inhibitor activity; ribosomal large subunit binding activity; and ribosomal small subunit binding activity. Involved in negative regulation of GTPase activity. Predicted to be part of messenger ribonucleoprotein complex and polysome. Predicted to be active in several cellular components, including neuron projection; nucleus; and synapse. Orthologous to human CPEB2 (cytoplasmic polyadenylation element binding protein 2). [provided by Alliance of Genome Resources, Apr 2022]