Mothers against decapentaplegic homolog 6

SMAD, Mothers against decapentaplegic homolog 6
Other names:	SMAD 6, Mothers against DPP homolog 6, Smad6, hSMAD6
Genetic data
Gene code:	HUGO code:SMAD6
Protein Structure/Function
Protein type:	I-SMAD (Inhibitory SMAD)
Functions:	signal transduction, transcription
Domains:	MH1, MH2
Other
Taxa expressing:	Homo sapiens; homologs: many metazoan phyla
Cell types:	ubiquitous; high levels in lungs
Subcellular localization:	Primary:nucleus, Alternative:cytoplasm
Covalent modifications:	phosphorylation

SMAD6 or mothers against decapentaplegic homolog 6 is a polypeptide that, as its name describes, is a homolog of the Drosophila gene "mothers against decapentaplegic". It belongs to the SMAD family of proteins, which belong to the TGFβ superfamily of modulators. Like many other TGFβ family members SMAD6 is involved in cell signalling. It acts as a regulator of TGFβ family (such as bone morphogenetic proteins) activity by competing with SMAD4 and preventing the transcription of SMAD4's gene products. There are two known isoforms of this protein.

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Identifiers
Symbol	SMAD6
Alt. Symbols	MADH6
Entrez	4091
HUGO	6772
OMIM	602931
RefSeq	NM_005585
UniProt	O43541
Other data
Locus	Chr. 15 q21-q22

Nomenclature

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).