Enables enzyme inhibitor activity. Involved in negative regulation of catalytic activity and regulation of circadian rhythm. Predicted to be located in several cellular components, including mitochondrial matrix; nucleoplasm; and spindle. Predicted to be part of DBIRD complex. Predicted to be active in nucleus. Is expressed in several structures, including central nervous system and retina. Orthologous to human CCAR2 (cell cycle and apoptosis regulator 2). [provided by Alliance of Genome Resources, Apr 2022]