Nocturnin (Noct), also known as Ccrn4l, is a protein encoded by the Noct gene. It belongs to the EEP family of proteins with similarity to the CCR4 family of deadenylases. Noct is an output of the circadian clock and helps adjust metabolism according to day-night activity. It is involved in multiple biological processes such as development, adipogenesis, lipid metabolism, inflammation, osteogenesis, and obesity [1]. It also plays a role in maintaining the homeostasis of nicotinamide adenine dinucleotide (NAD) and its phosphorylated form (NADP) by converting NADP(H) into NAD(H) [2].

Mice lacking Noct (Noct KO or Noct-/-) are protected from high-fat diet-induced obesity and hepatic steatosis, suggesting its role in lipid metabolism and obesity-related diseases [1]. A mouse model overexpressing Noct in vivo showed that transgenic male mice had lower fat mass compared to controls, likely through its role as a mediator of mitochondrial function [3].

In conclusion, Noct plays essential roles in metabolism-related biological processes, especially in lipid metabolism and adipocyte function. Studies using Noct KO mouse models have provided valuable insights into its role in obesity-related diseases, highlighting its potential as a target for treating metabolic disorders [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/