Cell proliferation in tissues, the specific fate of cells during embryo development, differentiation, and cell death are all controlled by various signals between cells. If this control is disrupted, serious consequences can occur. One prominent group of regulatory signals is the TGF-Beta superfamily, which includes a variety of peptide growth factors such as TGF-Beta itself, BMP (bone morphogenetic protein), and GDF (growth and differentiation factor). Members of the TGF-Beta family are expressed at different times and in tissue-specific forms, playing crucial roles in the development, homeostasis, and repair of most tissues in the body. All immune cells, including B cells, T cells, dendritic cells, and macrophages, secrete TGF-Beta, which in turn regulates the proliferation, differentiation, and activation of immune cells through other cytokines. Therefore, TGF-Beta is an effective immunosuppressant, and disruptions in TGF-β signaling are associated with autoimmune diseases, inflammation, and cancer.
