X-box-binding protein 1 (XBP1) is a 261-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P17861.
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The mean pLDDT of this model is 68.3 (low 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 | 30% |
| 70 to 90 | Confident: backbone generally right | 14% |
| 50 to 70 | Low: treat with caution | 26% |
| Below 50 | Very low: often disordered regions | 30% |
What pLDDT means and how to read it
Functions as a transcription factor during endoplasmic reticulum (ER) stress by regulating the unfolded protein response (UPR). Required for cardiac myogenesis and hepatogenesis during embryonic development, and the development of secretory tissues such as exocrine pancreas and salivary gland (By similarity). Involved in terminal differentiation of B lymphocytes to plasma cells and production of immunoglobulins (PubMed:11460154). Modulates the cellular response to ER stress in a PIK3R-dependent manner (PubMed:20348923). Binds to the cis-acting X box present in the promoter regions of major histocompatibility complex class II genes (PubMed:8349596). Involved in VEGF-induced endothelial cell…
Interacts with HM13 (PubMed:25239945). Interacts with RNF139; the interaction induces ubiquitination and degradation of isoform 1 (PubMed:25239945). Interacts (via luminal domain) with DERL1; the interaction obviates the need for ectodomain shedding prior to HM13/SPP-mediated XBP1 isoform 1 cleavage (PubMed:25239945). Interacts with isoform 2; the interaction sequesters isoform 2 from the…
Endoplasmic reticulum, Nucleus, Cytoplasm, Endoplasmic reticulum membrane, Membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 9NDP | EM | 2.82 Å | NB=237-260 |
| 6R5Q | EM | 3.0 Å | 1=237-260 |
| 6R6P | EM | 3.1 Å | 1=237-260 |
| 6R6G | EM | 3.7 Å | 1=237-260 |
| 6R7Q | EM | 3.9 Å | 1=237-260 |
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