Smad3 is a 50 kDa member of a family of proteins that act as key mediators of TGF beta superfamily signaling in cell proliferation, differentiation and development. The Smad family is divided into three subclasses: receptor regulated Smads, activin/TGF beta receptor regulated (Smad2 and 3) or BMP receptor regulated (Smad 1, 5, and 8), the common partner, (Smad4) that functions via its interaction to the various Smads, and the inhibitory Smads, (Smad6 and 7). Activated Smad3 oligomerizes with Smad4 upon TGF beta stimulation and translocates as a complex into the nucleus, allowing its binding to DNA and transcription factors. Phosphorylation of the two TGF beta dependent serines 423 and 425 in the C terminus of Smad3 is critical for Smad3 transcriptional activity and TGF beta signaling.
Synonyms: Smad3 phospho Ser423, Smad3 phospho S423, p-Smad3 Ser423, hMAD 3, hSMAD3, HSPC193, JV15 2, JV152, MAD mothers against decapentaplegic Drosophila homolog 3, MAD3, MADH 3, MADH3, Mothers against decapentaplegic homolog 3, Mothers against DPP homolog 3, SMA and MAD related protein 3, SMAD 3, SMAD, SMAD-3, SMAD3_HUMAN.