SMAD4 (D3R4N) XP^® Rabbit mAb (BSA and Azide Free) recognizes endogenous levels of total SMAD4 protein.

Monoclonal antibody is produced by immunizing animals with recombinant protein corresponding to human SMAD4 protein. The epitope has been mapped to residues surrounding Ser315.

Members of the SMAD family of signal transduction molecules are components of a critical intracellular pathway that transmits TGF-β 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, 9; the common-mediator SMAD (co-SMAD), SMAD4; and the antagonistic or inhibitory SMADs (I-SMADs), SMAD6 and 7 (1-5). Activated type I receptors associate with specific R-SMADs and phosphorylate them on a conserved SSXS motif in the carboxy-terminus. Phosphorylated R-SMADS dissociate from the receptor and form a heteromeric complex with SMAD4, initiating translocation of the heteromeric SMAD complex to the nucleus. Once in the nucleus, SMADs recruit a variety of DNA binding proteins that function to regulate transcriptional activity (6-8).