IMPDH2, or inosine 5'-monophosphate dehydrogenase type II, is a key enzyme in the de novo biosynthesis of guanine nucleotides, a dopamine synthetic pathway. It's involved in multiple biological processes such as cell cycle regulation, DNA damage response, and GTP synthesis [1,2,3].

In various disease models, IMPDH2 has shown significant impacts. In colorectal cancer, its overexpression promotes cell proliferation, invasion, migration, and epithelial-mesenchymal transition (EMT) via activation of the PI3K/AKT/mTOR and PI3K/AKT/FOXO1 pathways, while knockdown has the opposite effect [1]. In osteoclastogenesis, Impdh2 deficiency in mouse myeloid lineage cells reduces osteoclast number and alleviates ovariectomy-induced osteoporosis by impairing mitochondrial oxidative phosphorylation [4]. In hepatoblastoma, IMPDH2 overexpression is associated with poor patient outcomes, and its knockdown inhibits cell proliferation and induces cell cycle arrest [5].

In conclusion, IMPDH2 plays essential roles in processes like cell cycle regulation, GTP synthesis, and cell-specific functions. Studies using gene-knockout or knockdown models in various disease areas such as cancer and osteoporosis have revealed its significance, suggesting it could be a potential biomarker and therapeutic target for these diseases [1,4,5].