SMAD1 belongs to theSMAD, a family of proteins similar to the gene products of theDrosophila gene 'mothers against decapentaplegic' (Mad) and theC. elegans gene Sma.[citation needed] The name is a combination of the two; and based on a tradition of such unusual naming within the gene research community.[6]
It was found that a mutation in the 'Drosophila' gene,MAD, in the mother, repressed the gene,decapentaplegic, in the embryo. Mad mutations can be placed in an allelic series based on the relative severity of the maternal effect enhancement of weak dpp alleles, thus explaining the name Mothers against dpp.[7]
SMAD proteins are signal transducers and transcriptional modulators that mediate multiple signaling pathways. This protein mediates the signals of thebone morphogenetic proteins (BMPs), which are involved in a range of biological activities including cell growth,apoptosis,morphogenesis,development and immune responses. In response to BMP ligands, this protein can bephosphorylated and activated by the BMP receptor kinase. The phosphorylated form of this protein forms a complex withSMAD4, which is important for its function in the transcription regulation. This protein is a target for SMAD-specificE3 ubiquitin ligases, such asSMURF1 andSMURF2, and undergoes ubiquitination andproteasome-mediated degradation. Alternatively spliced transcript variants encoding the same protein have been observed.[8]
^Riggins GJ, Thiagalingam S, Rozenblum E, Weinstein CL, Kern SE, Hamilton SR, Willson JK, Markowitz SD, Kinzler KW, Vogelstein B (July 1996). "Mad-related genes in the human".Nature Genetics.13 (3):347–9.doi:10.1038/ng0796-347.PMID8673135.S2CID10124489.
