Transmembrane protein 50B (TMEM50B)

Transmembrane protein 50B (TMEM50B), also known as C21orf4 or HCV p7-trans-regulated protein 3 (p7TP3), is a human transmembrane protein encoded by the TMEM50B gene on chromosome 21q22.11[1][2][4]. It is a relatively small protein (158 residues) predicted to play a role in the late endosome to vacuole transport via the multivesicular body sorting pathway and is localized to the endoplasmic reticulum[1][7]. TMEM50B has been identified as a potential tumor suppressor, particularly in liver cancer, where increased expression inhibits cancer cell migration, invasion, adhesion, proliferation, and enforces G0/G1 cell cycle arrest by suppressing the Wnt/β-catenin pathway[2][5]. Clinically, TMEM50B expression is robustly increased by nucleos(t)ide analogs such as tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF); this upregulation prolongs cell cycle arrest and promotes apoptosis in HepG2 and Huh7 liver cancer cells, suggesting a protective anti-cancer mechanism[2]. Previous data also indicate that TMEM50B may be involved in the development of the brain, given its overexpression in Down syndrome models[2]. No direct established role as a standard therapeutic target (such as a receptor, ion channel, or enzyme), nor direct safety concerns or conventional interacting drugs beyond TDF/TAF, have been reported[2][5][1].

Other names

C21orf4HCV p7-trans-regulated protein 3HCV p7-transregulated protein 3HCVP7TP3UNQ167/PRO193

Drugs up-regulate TMEM50B (p7TP3) expression, thus inhibiting cancer cell migration, invasion, proliferation and facilitating apoptosis via suppression of the Wnt/β-catenin signaling pathway