Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform (PIK3CA) is a 1068-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P42336.
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The mean pLDDT of this model is 92.4 (very high 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 | 82% |
| 70 to 90 | Confident: backbone generally right | 12% |
| 50 to 70 | Low: treat with caution | 5% |
| Below 50 | Very low: often disordered regions | 1% |
What pLDDT means and how to read it
Phosphoinositide-3-kinase (PI3K) phosphorylates phosphatidylinositol (PI) and its phosphorylated derivatives at position 3 of the inositol ring to produce 3-phosphoinositides (PubMed:15135396, PubMed:23936502, PubMed:28676499). Uses ATP and PtdIns(4,5)P2 (phosphatidylinositol 4,5-bisphosphate) to generate phosphatidylinositol 3,4,5-trisphosphate (PIP3) (PubMed:15135396, PubMed:28676499). PIP3 plays a key role by recruiting PH domain-containing proteins to the membrane, including AKT1 and PDPK1, activating signaling cascades involved in cell growth, survival, proliferation, motility and morphology. Participates in cellular signaling in response to various growth factors. Involved in the…
Heterodimer of a catalytic subunit PIK3CA and a p85 regulatory subunit (PIK3R1, PIK3R2 or PIK3R3) (PubMed:26593112). Interacts with IRS1 in nuclear extracts (By similarity). Interacts with RUFY3 (By similarity). Interacts with RASD2 (By similarity). Interacts with APPL1. Interacts with HRAS and KRAS (By similarity). Interaction with HRAS/KRAS is required for PI3K pathway signaling and cell…
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 9CMK | X-ray | 1.75 Å | A/B=160-300 |
| 9ASF | X-ray | 1.77 Å | C=1046-1054 |
| 9CX0 | X-ray | 1.92 Å | C=1046-1054 |
| 7L1C | X-ray | 1.96 Å | C=1046-1054 |
| 9CWY | X-ray | 1.98 Å | C=1046-1054 |
| 8EXL | X-ray | 1.99 Å | A=7-1052 |
| 9CX1 | X-ray | 2.0 Å | C=1046-1054 |
| 9CML | X-ray | 2.01 Å | A/B=160-300 |
| 9ASG | X-ray | 2.03 Å | C=1046-1054 |
| 7L1B | X-ray | 2.04 Å | C=1046-1054 |
| 9CWZ | X-ray | 2.05 Å | C=1046-1054 |
| 7JIU | X-ray | 2.12 Å | A=107-1052 |
| 7RRG | X-ray | 2.12 Å | C=1046-1054 |
| 6PYS | X-ray | 2.19 Å | A=107-1051 |
| 4JPS | X-ray | 2.2 Å | A=1-1068 |
| 7PG5 | X-ray | 2.2 Å | A=1-1068 |
| 9B4U | X-ray | 2.21 Å | A/B=157-300 |
| 5DXT | X-ray | 2.25 Å | A=107-1068 |
| 8SBC | X-ray | 2.3 Å | A=1-1068 |
| 9CX2 | X-ray | 2.3 Å | C=1046-1054 |
Showing 20 of 125 experimental structures (best resolution first).
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