Human Smad2 Antibody

SMAD2 (Sma and MAD-related protein 2; also MAD2, MADR2 and MADH2) is a 58-62 kDa member of the dwarfin/SMAD family of proteins. It is widely expressed, particularly in striated muscle, and exists constitutively in the cytoplasm. SMAD2 is a downstream mediator of TGF-beta and activin signaling. In particular, SMAD2 is a nonphosphorylated monomer in unstimulated cells. Upon ALK-4, -5, and -7 receptor activation, SMAD2 is phosphorylated and forms either homotrimers or heterotrimers with SMAD3 and SMAD4. These heterotrimers enter the nucleus and initiate gene transcription. Human SMAD2 is 467 amino acids (aa) in length. It contains one regulatory MH domain (aa 120-176) and a transactivation MH domain (aa 274-467). There are at least five utilized phosphorylation sites and one acetylation site at Lys19 that promotes transcriptional activity. There are four potential isoform variants. One shows a deletion of aa 79-108, while another contains the same deletion coupled to another deletion of aa 219-243. A third shows a deletion of aa 344-358, and a fourth is missing aa 221-225. Over aa 20-108, human SMAD2 shares 98% aa identity with mouse SMAD2.