Ptpn9, also named PTP-MEG2, is an important member of the protein tyrosine phosphatase family. It plays a role in various biological processes by regulating protein phosphorylation. It is involved in pathways such as those related to FGFR2 phosphorylation, autophagy, and may be associated with diseases like cholangiocarcinoma, melanoma, esophageal squamous cell carcinoma, and more [1,2,3,4]. Genetic models are valuable for studying its functions.

In cholangiocarcinoma, Ptpn9 interacts with FGFR2 and negatively regulates FGFR2 pY656/657 phosphorylation through interaction with ACAP1. Co-expression of Ptpn9 and ACAP1 indicates a favorable prognosis. Also, a substitution in FGFR2 can decrease the Ptpn9-FGFR2 interaction and pemigatinib effectiveness. Ptpn9 enhances pemigatinib's effectiveness and suppresses cholangiocarcinoma proliferation, migration, and invasion [1]. In autophagy, depletion of Ptpn9 and its Drosophila homolog impaired autophagosome formation and autophagic flux. Ptpn9 is essential for homotypic fusion of ATG16L1 + vesicles during starvation-induced autophagy by dephosphorylating VTI1B [2].

In conclusion, Ptpn9 is crucial in regulating phosphorylation-related biological processes. Its role in cholangiocarcinoma and autophagy, as revealed through functional studies, highlights its significance in understanding disease mechanisms. Research on Ptpn9 using genetic models contributes to the exploration of potential therapeutic targets for related diseases.