Transmembrane Protein 119 (TMEM119)

Tmem119 was selected based on its rapid induction by PTH independent of later increases in endogenous TGF-β. Levels of Tmem119 increased with time in cultures of MC3T3-E1 cells and mouse mesenchymal ST-2 cells committed to the osteoblast lineage by BMP-2. PTH stimulated Tmem119 levels within 1 hr by western blot analysis and immunocytochemistry in MC3T3-E1 cells. MC3T3-E1 cells stably overexpressing Tmem119 exhibited elevated levels of Runx2, osteocalcin, alkaline phosphatase and β-catenin, while Tmem119 augmented BMP-2-induced Runx2 levels in mesenchymal cells. Tmem119 interacted with Runx2 and Smad1 and Smad5 in C2C12 cells. Tmem119 is induced by PTH, and promotes differentiation in mouse osteoblastic cells.