Nocturnin (Noct), also known as Ccrn4l, is a protein whose gene is an output of the circadian clock. It belongs to the EEP family of proteins, showing similarity to the CCR4 family of deadenylases. Noct helps the circadian clock adjust metabolism according to day-night activity and is involved in regulating the homeostasis of nicotinamide adenine dinucleotide cofactors NAD(H) and NADP(H), with its role spanning various metabolic pathways [1,2].

Mice lacking Noct (Noct KO or Noct-/-) are protected from high-fat diet-induced obesity and hepatic steatosis, indicating its role in lipid metabolism and obesity-related conditions [1]. A mouse model overexpressing Noct showed decreased fat mass in male mice, likely through its role as a mediator of mitochondrial function in adipocytes [3].

In conclusion, Noct plays a crucial role in metabolism-related biological functions, especially in lipid metabolism, obesity, and the regulation of NAD(H) and NADP(H) homeostasis. The use of Noct KO mouse models has been instrumental in revealing its role in these disease-related areas, such as obesity and hepatic steatosis [1,3].

References:

1. Kulshrestha, Shruti, Devkar, Ranjitsinh. 2023. Circadian control of Nocturnin and its regulatory role in health and disease. In Chronobiology international, 40, 970-981. doi:10.1080/07420528.2023.2231081. https://pubmed.ncbi.nlm.nih.gov/37400970/

2. Chen, Luojun, Xing, Xiaoke, Zhang, Pingfeng, Chen, Lulu, Pei, Huadong. 2023. Homeostatic regulation of NAD(H) and NADP(H) in cells. In Genes & diseases, 11, 101146. doi:10.1016/j.gendis.2023.101146. https://pubmed.ncbi.nlm.nih.gov/38988322/

3. Le, Phuong T, Bornstein, Sheila A, Motyl, Katherine J, Rosen, Clifford J, Guntur, Anyonya R. 2019. A novel mouse model overexpressing Nocturnin results in decreased fat mass in male mice. In Journal of cellular physiology, 234, 20228-20239. doi:10.1002/jcp.28623. https://pubmed.ncbi.nlm.nih.gov/30953371/