TWEAK belongs to the TNF family of ligands and signals through TWEAKR also known as TNFRSF12A. TWEAK is expressed in a variety of tissues, including the adult heart, pancreas, skeletal muscle, small intestine, spleen and peripheral blood lymphocytes. TWEAK has the ability to induce NFkB activation and chemokine secretion, and to exert an apoptotic activity in certain cells, such as HT-29 human adenocarcinoma cells when cultured in the presence of IFN-γ. TWEAK also promotes proliferation and migration of endothelial cells. Recombinant human TWEAK is a soluble 17.0 kDa polypeptide (154 amino acid residues) comprising the TNF homologous region of TWEAK and is generated by proteolytic processing of the full length membrane anchored TWEAK protein.