Mothers against decapentaplegic homolog 2

SMAD family member 2
File:PBB Protein SMAD2 image.jpg PDB rendering based on 1dev.
Available structures PDB Ortholog search: Template:Homologene2PDBe PDBe, Template:Homologene2uniprot RCSB List of PDB id codes 1dev​, 1khx​, 1mjs​, 1mk2​, 1u7f​, 1u7v​
Identifiers
Symbols	SMAD2 ; JV18; JV18-1; MADH2; MADR2; MGC22139; MGC34440; hMAD-2; hSMAD2
External IDs	Template:OMIM5 Template:MGI HomoloGene: 21197
Gene ontology Molecular function Template:GNF GO Template:GNF GO Template:GNF GO Cellular component Template:GNF GO Template:GNF GO Template:GNF GO Biological process Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO
RNA expression pattern
File:PBB GE SMAD2 203075 at tn.png
File:PBB GE SMAD2 203076 s at tn.png
File:PBB GE SMAD2 203077 s at tn.png
More reference expression data
Orthologs
Template:GNF Ortholog box
Species	Human	Mouse
Entrez	n/a	n/a
Ensembl	n/a	n/a
UniProt	n/a	n/a
RefSeq (mRNA)	n/a	n/a
RefSeq (protein)	n/a	n/a
Location (UCSC)	n/a	n/a
PubMed search	n/a	n/a

SMAD2 or Mothers against decapentaplegic homolog 2 is a proteine 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 SMAD2 is involved in cell signalling. SMAD2 modulates signals of activin and TGFβ's. It interacts with SMAD anchor for receptor activation (SARA).The binding of ligands causes the phosphorylation of the SMAD2 protein and the dissociation from SARA and the association with SMAD4. It is subsequently transferred to the nucleus where it forms complexes with other proteins and acts as a transcription factor. SMAD2 is a receptor regulated SMAD (R-SMAD) and is activated by bone morphogenetic protein type 1 receptor kinase. The protein encoded by this gene belongs to the SMAD, a family of proteins similar to the gene products of the Drosophila gene 'mothers against decapentaplegic' (Mad) and the C. elegans gene Sma. SMAD proteins are signal transducers and transcriptional modulators that mediate multiple signaling pathways. This protein mediates the signal of the transforming growth factor (TGF)-beta, and thus regulates multiple cellular processes, such as cell proliferation, apoptosis, and differentiation. This protein is recruited to the TGF-beta receptors through its interaction with the SMAD anchor for receptor activation (SARA) protein. In response to TGF-beta signal, this protein is phosphorylated by the TGF-beta receptors. The phosphorylation induces the dissociation of this protein with SARA and the association with the family member SMAD4. The association with SMAD4 is important for the translocation of this protein into the nucleus, where it binds to target promoters and forms a transcription repressor complex with other cofactors. This protein can also be phosphorylated by activin type 1 receptor kinase, and mediates the signal from the activin. Alternatively spliced transcript variants encoding the same protein have been observed.

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). The nomenclature for this protein, like that of Sonic hedgehog, has been criticized for its frivolity.

Further reading

• Wrana JL (1998). "TGF-beta receptors and signalling mechanisms". Mineral and electrolyte metabolism. 24 (2–3): 120–30. PMID 9525694.
• Massagué J (1998). "TGF-beta signal transduction". Annu. Rev. Biochem. 67: 753–91. doi:10.1146/annurev.biochem.67.1.753. PMID 9759503.
• Verschueren K, Huylebroeck D (2000). "Remarkable versatility of Smad proteins in the nucleus of transforming growth factor-beta activated cells". Cytokine Growth Factor Rev. 10 (3–4): 187–99. PMID 10647776.
• Wrana JL, Attisano L (2000). "The Smad pathway". Cytokine Growth Factor Rev. 11 (1–2): 5–13. PMID 10708948.
• Miyazono K (2000). "TGF-beta signaling by Smad proteins". Cytokine Growth Factor Rev. 11 (1–2): 15–22. PMID 10708949.
• Zannis VI, Kan HY, Kritis A; et al. (2001). "Transcriptional regulation of the human apolipoprotein genes". Front. Biosci. 6: D456–504. PMID 11229886.CS1 maint: Explicit use of et al. (link) CS1 maint: Multiple names: authors list (link)