PIK3CB
Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit beta
Gene Information Card
| Symbol | PIK3CB |
|---|---|
| Full Name | Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit beta |
| Gene Type | protein-coding |
| Chromosomal Location | 3q22.3 |
| NCBI Gene ID | 5291 ncbi.nlm.nih.gov/gene/5291 |
| Ensembl ID | ENSG00000051382 |
| UniProt ID | P42338 |
| OMIM ID | 602925 |
| HGNC ID | 8980 |
| Aliases | PI3Kbeta, PIK3C1, p110beta |
Description
PIK3CB encodes the p110β catalytic subunit of class I phosphatidylinositol 3-kinase (PI3K). This enzyme phosphorylates phosphatidylinositol-4,5-bisphosphate to generate phosphatidylinositol-3,4,5-trisphosphate, a key second messenger that activates downstream signaling pathways including AKT/mTOR, regulating cell growth, proliferation, survival, and metabolism. PIK3CB is ubiquitously expressed and plays a critical role in insulin signaling and oncogenesis.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Colorectal cancer | Activating mutations and copy number gains lead to increased PI3K/AKT signaling, promoting tumor growth | COSMIC, ClinVar |
| Breast cancer | Overexpression and mutations in PIK3CB contribute to PI3K pathway hyperactivation, associated with resistance to targeted therapies | COSMIC, NCBI Gene |
| Prostate cancer | PIK3CB amplification and mutations drive PI3K/AKT signaling, linked to disease progression and metastasis | COSMIC, OMIM |
| Glioblastoma | PIK3CB mutations and copy number alterations activate PI3K signaling, enhancing tumor cell proliferation and survival | COSMIC, ClinVar |
| Endometrial cancer | PIK3CB mutations, including hotspot variants, activate the PI3K pathway, contributing to tumorigenesis | COSMIC |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 10.2 | Medium |
| Breast | 7.8 | Medium |
| Colon | 6.5 | Medium |
| Prostate | 8.1 | Medium |
| Lung | 7.0 | Medium |
| Liver | 5.3 | Low |
| Kidney | 6.9 | Medium |
| Testis | 9.5 | Medium |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 12.4 | High expression |
| HeLa | 9.8 | Medium expression |
| MCF7 | 8.5 | Medium expression |
| A549 | 7.2 | Medium expression |
| PC3 | 10.1 | High expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1624G>A (p.Glu542Lys) | Missense | <1% | Activating; increases kinase activity and downstream AKT signaling |
| c.1633G>A (p.Glu545Lys) | Missense | <1% | Activating; hotspot mutation in helical domain |
| c.3140A>G (p.His1047Arg) | Missense | <1% | Activating; kinase domain mutation enhancing lipid kinase activity |
| c.1624G>C (p.Glu542Gln) | Missense | <0.5% | Activating; similar effect to Glu542Lys |
| c.1634A>G (p.Glu545Gly) | Missense | <0.5% | Activating; helical domain mutation |
Mutation functional classification
Loss of Function (LOF)
Rare truncating or missense mutations that reduce kinase activity, potentially impairing PI3K signaling.
Gain of Function (GOF)
Common hotspot mutations (e.g., Glu542Lys, His1047Arg) that increase lipid kinase activity and constitutive AKT activation.
Dominant Negative (DN)
Not well characterized; some mutations may interfere with regulatory subunit binding, but evidence is limited.
View complete mutation data：
Gene Ontology (GO)
| • GO:0005524 - ATP binding | • GO:0016303 - 1-phosphatidylinositol-3-kinase activity |
| • GO:0046934 - phosphatidylinositol-4 | • 5-bisphosphate 3-kinase activity |
| • GO:0008286 - insulin receptor signaling pathway | • GO:0048015 - phosphatidylinositol-mediated signaling |
| • GO:0007165 - signal transduction | • GO:0008284 - positive regulation of cell population proliferation |
| • GO:0043066 - negative regulation of apoptotic process |
Pathways
• PI3K-Akt signaling pathway (KEGG: hsa04151)
• EGFR tyrosine kinase inhibitor resistance (KEGG: hsa01521)
• Endocrine resistance (KEGG: hsa01522)
• Insulin signaling pathway (KEGG: hsa04910)
• mTOR signaling pathway (KEGG: hsa04150)
• Focal adhesion (KEGG: hsa04510)
Protein Summary
PIK3CB encodes the p110β catalytic subunit of class IA PI3K. The protein contains an N-terminal adaptor-binding domain (ABD) that interacts with p85 regulatory subunits, a Ras-binding domain (RBD), a C2 domain, a helical domain, and a C-terminal kinase domain. p110β is unique among class I PI3Ks in its ability to be activated by both receptor tyrosine kinases and G protein-coupled receptors. It is essential for insulin signaling and glucose metabolism, and its dysregulation is implicated in various cancers. The protein is a target for isoform-selective PI3K inhibitors in clinical development.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| PIK3CB Knockout HEK293 Cell Line | EDJ-KQ519 | Human | 5291 | Details Get a Quote |
| PIK3CB Knockout HeLa Cell Line | EDJ-KQ18015 | Human | 5291 | Details Get a Quote |
| PIK3CB Knockout A-549 Cell Line | EDJ-KQ18127 | Human | 5291 | Details Get a Quote |
| PIK3CB Knockout HCT 116 Cell Line | EDJ-KQ18851 | Human | 5291 | Details Get a Quote |
| PIK3CB Knockout Hep-G2/DOX Cell Line | EDC07582 | Human | 5291 | Details Get a Quote |
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