Polymeric immunoglobulin receptor (PIGR) is a 764-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P01833.
Explore in 3D Color by confidence AlphaFold DB UniProt
The mean pLDDT of this model is 76.7 (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 | 45% |
| 70 to 90 | Confident: backbone generally right | 27% |
| 50 to 70 | Low: treat with caution | 7% |
| Below 50 | Very low: often disordered regions | 21% |
What pLDDT means and how to read it
Mediates selective transcytosis of polymeric IgA and IgM across mucosal epithelial cells. Binds polymeric IgA and IgM at the basolateral surface of epithelial cells. The complex is then transported across the cell to be secreted at the apical surface. During this process, a cleavage occurs that separates the extracellular (known as the secretory component) from the transmembrane segment
Interacts (mainly via CDR1-like domain) with dimeric IgA (PubMed:15530357). Interacts (mainly via CDR2-like domain) with pentameric IgM (PubMed:10229845, PubMed:32029689)
Cell membrane, Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 3CHN | Other | 1.0 Å | J=353-458, S=19-603 |
| 3CM9 | Other | 1.0 Å | J=353-458, S=19-603 |
| 1XED | X-ray | 1.9 Å | A/B/C/D/E/F=19-127 |
| 5D4K | X-ray | 2.6 Å | A/B=19-565 |
| 6UE7 | EM | 2.9 Å | C=19-603 |
| 6UE9 | EM | 2.9 Å | C=19-603 |
| 6UE8 | EM | 3.0 Å | C=19-603 |
| 6UEA | EM | 3.0 Å | C=19-603 |
| 8SKV | EM | 3.1 Å | E=19-565 |
| 6LX3 | EM | 3.15 Å | P=1-565 |
| 7YSG | EM | 3.18 Å | P=19-559 |
| 8SKU | EM | 3.2 Å | E=19-565 |
| 6LXW | EM | 3.27 Å | P=1-565 |
| 7K0C | EM | 3.3 Å | C=19-603 |
| 6KXS | EM | 3.4 Å | P=19-565 |
| 2OCW | X-ray | A=19-603 |
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