Enables RNA cap binding activity. Predicted to be involved in defense response to virus. Predicted to act upstream of or within 7-methylguanosine mRNA capping and mRNA transport. Predicted to be located in cytoplasm and nuclear speck. Predicted to be active in nucleus. Is expressed in several structures, including brain; cardiovascular system; genitourinary system; gut; and immune system. Orthologous to human NCBP3 (nuclear cap binding subunit 3). [provided by Alliance of Genome Resources, Apr 2022]