CD109 encodes a glycosyl phosphatidylinositol (GPI)-linked glycoprotein that localizes to the surface of platelets, activated T-cells, and endothelial cells. The protein binds to and negatively regulates signalling by transforming growth factor beta (TGF-beta). Multiple transcript variants encoding different isoforms have been found for CD109. CD109 (CD109 Molecule) is a Protein Coding gene. Diseases associated with CD109 include Fetal And Neonatal Alloimmune Thrombocytopenia and Epithelioid Sarcoma. Among its related pathways are Response to elevated platelet cytosolic Ca2+ and Metabolism of proteins.