SMAD2, 3 (Mothers Against Decapentaplegic Homolog 2, MAD Homolog 2, Mothers Against DPP Homolog 2, JV18-1, Mad-related Protein 2, hMAD-2, SMAD Family Member 2, SMAD 2, MADH2, MADR2/Mothers Against Decapentaplegic Homolog 3, MAD Homolog 3, Mad3, Mothers Against DPP Homolog 3, hMAD-3, JV15-2, SMAD Family Member 3, SMAD 3, MADH3)

Members of the Smad family of signal transduction molecules are components of a critical intracellular pathway that transmit TGF-b signals from the cell surface into the nucleus. Three distinct classes of Smads have been defined: the receptor-regulated Smads (R-Smads), which include Smad1, 2, 3, 5, and 8; the common-mediator Smad (co-Smad), Smad4; and the antagonistic or inhibitory Smads (I-Smads), Smad6 and 7. Activated type I receptors associate with specific R-Smads and phosphorylate them on a conserved carboxy-terminal SSXS motif. The phosphorylated R-Smad dissociates from the receptor and...