Nprl2, also known as nitrogen permease regulator-like 2, is a critical component of the GATOR1 (Gap Activity TOward Rags 1) complex. GATOR1 functions as a negative regulator of the mammalian target of rapamycin complex 1 (mTORC1) kinase when intracellular amino acids are low. The mTORC1 signaling pathway is involved in various cellular processes such as growth, metabolism, and autophagy, highlighting the importance of Nprl2 in maintaining cellular homeostasis [1,2,3,4,5,6].

Loss-of-function studies have provided key insights into Nprl2's role. In mouse excitatory glutamatergic neurons, loss of Nprl2 expression causes seizures before death, increases mTORC1-dependent signal transduction, and alters amino acid homeostasis in the brain. It also reduces dendritic branching and increases the strength of electrically stimulated action potentials, consistent with elevated expression of epilepsy-linked voltage-gated sodium channels [1]. In hepatocellular carcinoma, down-regulation of Nprl2 significantly increases tumor proliferation, migration, and colony formation in vitro and in vivo, via mTOR pathway activation and autophagy suppression [2].

In conclusion, Nprl2 is essential for regulating mTORC1 signaling, which in turn impacts multiple cellular functions. Gene-knockout or conditional-knockout mouse models have been instrumental in revealing its role in diseases such as epilepsy and cancer. Understanding Nprl2's function provides potential therapeutic targets for these conditions [1,2].