Component of the na (narrow abdomen) sodium channel complex. In the circadian clock neurons it functions with na and unc79 to promote circadian rhythmicity. Interacts with unc79 and na. Can interact with unc79 independently of na. Severe disruptions in circadian rhythmicity. Decreases anticipatory behaviors and free-running rhythmicity. RNAi-mediated knockdown in pacemaker neurons decreases anticipatory behaviors under constant dark (DD) conditions but has no effect on light-dark (LD) rhythmic behavior. Belongs to the unc-80 family.