TMEM120B is a transmembrane protein with pleiotropic roles in cellular physiology and disease. Primary Function: TMEM120B functions as an ion channel and contributes to adipogenesis 1. It demonstrates stable ion transport capabilities across lipid bilayers and can bind coenzyme A (CoA-SH) and ATP at the single-molecule level, suggesting biosensor potential 1. In metabolic tissues, TMEM120B expression correlates with body weight and BMI, implicating it in adipogenic processes 2. Mechanism: In breast cancer, TMEM120B directly binds myosin heavy chain 9 (MYH9) through its coiled-coil domain, stabilizing MYH9 and preventing ubiquitin-dependent degradation 3. This interaction accelerates focal adhesion assembly and activates the β1-integrin/FAK-TAZ-mTOR signaling axis 3. In PCOS-associated oocyte dysfunction, TMEM120B functions as a competing endogenous RNA (ceRNA) regulated by the miR-92b-3p/PWRN2 axis 4. Disease Relevance: TMEM120B is upregulated in multiple cancers (lung, breast, gastric, colon, ovarian), correlating with advanced TNM stage and poor prognosis 3. Elevated TMEM120B promotes cancer stemness and chemotherapy resistance 3. It is also altered in primary open-angle glaucoma 5 and implicated in intellectual disability via 12q24.31 microdeletion 6. Clinical Significance: TMEM120B represents a potential therapeutic target in chemotherapy-resistant cancers and may serve as a prognostic biomarker for treatment outcomes.