MTMR7 (myotubularin-related protein 7) is a lipid phosphatase that specifically dephosphorylates phosphatidylinositol 3-phosphate (PtdIns(3)P) and inositol 1,3-bisphosphate, with a preference for water-soluble substrates 1. The protein localizes to Golgi-like granules and cytosol, and forms functional complexes with MTMR9, which enhances its phosphatase activity 1. MTMR7 functions as a tumor suppressor by inhibiting PI3K/AKT and ERK1/2 signaling pathways downstream of growth factor receptors 2. In reproductive biology, MTMR7 maintains spermatogonial stem cell homeostasis by preventing excessive proliferation through PI3K/AKT pathway inhibition 3 and regulates human spermatogonial stem cell proliferation and migration via FLNB-mediated β-catenin signaling 4. Additionally, MTMR7 directly binds and inhibits mutant K-RAS (G12V), reducing RAS GTPase activity and downstream oncogenic signaling 5. Recent findings identify MTMR7 as a novel STIM1-binding protein, linking phosphoinositide metabolism to store-operated calcium entry 6. Clinically, MTMR7 expression is reduced in colorectal cancer with advancing tumor grade and stage, and has been implicated as a genetic modifier in prion diseases 27.