Enables RNA 7-methylguanosine cap binding activity. Involved in several processes, including cellular response to insulin stimulus; negative regulation of synaptic vesicle recycling; and positive regulation of cell projection organization. Located in several cellular components, including dendritic spine; distal axon; and filopodium tip. Biomarker of temporal lobe epilepsy. Human ortholog(s) of this gene implicated in autism spectrum disorder and schizophrenia. Orthologous to human CYFIP1 (cytoplasmic FMR1 interacting protein 1). [provided by Alliance of Genome Resources, Apr 2022]