Receptors for the TGF-β Ligand Family

Abstract

This chapter summarizes the current status of research in the transforming growth factor-β (TGF-β) receptor field. The TGF-β is a group of multi-functional peptide hormones that regulate many aspects of cellular function. TGF-β is identified as a protein that induced normal rat kidney fibroblasts to proliferate in soft agar in the presence of epidermal growth factor (EGF). TGF-β can inhibit the differentiation of certain mesodermal cells, induce the differentiation of others, and inhibit proliferation of cells derived from epithelial, endothlial, neuronal, hematopoietic, lymphoid, and fibroblastic origins. The effects of TGF-β on individual cells, is also important in many biological processes. TGF-β is an important regulator of immune responses, wound healing, cell adhesion, cell-cell recognition, and extracellular matrix deposition. Deregulation of TGF-β function is implicated in the pathological processes of several diseases including arthritis, atheosclerosis, and glomerulonephritis. The cells that lose the ability to respond to TGF-β may exhibit uncontrolled proliferation and become tumorigenic. The TGF-β receptors transduce signals that result in TGF-β-induced gene responses and growth inhibition. The type I, II, and III receptors, are focused in the chapter as they are widely expressed and the most biologically relevant mediators of TGF-β signal transduction.