TMEFF1/Tomoregulin-1: ProductsTransmembrane Protein with EGF-like and two Follistatin-like domains 1 (TMEFF1) also known as tomoregulin-1 is a type I transmembrane glycoprotein. TMEFF1 contains two follistatin modules and an EGF domain in its extracellular domain, a transmembrane domain and a short cytoplasmic tail. The extracellular domain of TMEFF1 can be released as a soluble protein. TMEFF1 is predominantly expressed in brain, but is downregulated in brain neoplasms. TMEFF1 selectively regulates nodal but not activin signaling through direct binding to the nodal co-receptor, Cripto.