Mothers against decapentaplegic homolog 3 (SMAD3) is a 425-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P84022.
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The mean pLDDT of this model is 83.6 (confident overall). pLDDT is AlphaFold's per-residue confidence score from 0 to 100. In MolViewer, choose the B-factor color scheme to color the model by pLDDT, because AlphaFold stores it in the B-factor column.
| pLDDT band | Meaning | Share of residues |
|---|---|---|
| Above 90 | Very high: backbone and side chains are usually accurate | 66% |
| 70 to 90 | Confident: backbone generally right | 14% |
| 50 to 70 | Low: treat with caution | 3% |
| Below 50 | Very low: often disordered regions | 17% |
What pLDDT means and how to read it
Receptor-regulated SMAD (R-SMAD) that is an intracellular signal transducer and transcriptional modulator activated by TGF-beta (transforming growth factor) and activin type 1 receptor kinases. Binds the TRE element in the promoter region of many genes that are regulated by TGF-beta and, on formation of the SMAD3/SMAD4 complex, activates transcription. Also can form a SMAD3/SMAD4/JUN/FOS complex at the AP-1/SMAD site to regulate TGF-beta-mediated transcription. Has an inhibitory effect on wound healing probably by modulating both growth and migration of primary keratinocytes and by altering the TGF-mediated chemotaxis of monocytes. This effect on wound healing appears to be…
Monomer; in the absence of TGF-beta (PubMed:9670020). Homooligomer; in the presence of TGF-beta (PubMed:9670020). Heterotrimer; forms a heterotrimer in the presence of TGF-beta consisting of two molecules of C-terminally phosphorylated SMAD2 or SMAD3 and one of SMAD4 to form the transcriptionally active SMAD2/SMAD3-SMAD4 complex (PubMed:11224571, PubMed:15350224, PubMed:15799969,…
Cytoplasm, Nucleus
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 6YIB | X-ray | 1.7 Å | P=417-425 |
| 1MJS | X-ray | 1.91 Å | A=229-425 |
| 5OD6 | X-ray | 2.0 Å | A/B=11-135 |
| 5ODG | X-ray | 2.12 Å | A/B=11-135 |
| 6ZMN | X-ray | 2.33 Å | A/B=10-136 |
| 1OZJ | X-ray | 2.4 Å | A/B=1-144 |
| 5XOC | X-ray | 2.4 Å | A=220-416 |
| 1U7F | X-ray | 2.6 Å | A/C=228-425 |
| 1MK2 | X-ray | 2.74 Å | A=220-425 |
| 1MHD | X-ray | 2.8 Å | A/B=1-132 |
| 2LAJ | NMR | B=202-211 | |
| 2LB2 | NMR | B=178-189 |
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