SMAD (protein)

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SMAD's (Small Mothers Against Decapentaplegic) are a class of proteins that modulate the activity of transforming growth factor beta ligands.

The SMAD's form complexes, often with other SMAD's, enter the nucleus and serve as transcription factors.


There are three classes of SMAD:


The SMAD proteins are homologs of both the drosophila protein, mothers against decapentaplegic (MAD) and the C. elegans protein SMA. The name is a combination of the two.

During Drosophila research, it was found that a mutation in the gene, MAD, in the mother, repressed the gene, decapentaplegic, in the embryo. The phrase "Mothers against" was added since mothers often form organizations opposing various issues eg. Mothers Against Drunk Driving or (MADD).


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