This gene encodes a member of the Smad family of signal transduction proteins. Smad proteins are phosphorylated and activated by transmembrane serine-threonine receptor kinases in response to TGF-beta signaling. The product of this gene forms homomeric complexes and heteromeric complexes with other activated Smad proteins, which then accumulate in the nucleus and regulate the transcription of target genes. This protein binds to DNA and recognizes an 8-bp palindromic sequence (GTCTAGAC) called the Smad-binding element (SBE). The Smad proteins are subject to complex regulation by post-translational modifications. Mutations or deletions in this gene have been shown to result in pancreatic cancer, juvenile polyposis syndrome, and hereditary hemorrhagic telangiectasia syndrome. SMAD4 (SMAD Family Member 4) is a Protein Coding gene. Diseases associated with SMAD4 include Myhre Syndrome and Polyposis, Juvenile Intestinal. Among its related pathways are PEDF Induced Signaling and Validated targets of C-MYC transcriptional repression. GO annotations related to this gene include transcription factor activity, sequence-specific DNA binding and sequence-specific DNA binding. An important paralog of this gene is SMAD9.