INPP4B
Inositol Polyphosphate-4-Phosphatase Type II B
Gene Information Card
| Symbol | INPP4B |
|---|---|
| Full Name | Inositol Polyphosphate-4-Phosphatase Type II B |
| Gene Type | protein-coding |
| Chromosomal Location | 4q31.21 |
| NCBI Gene ID | 8821 ncbi.nlm.nih.gov/gene/8821 |
| Ensembl ID | ENSG00000109452 |
| UniProt ID | O15327 |
| OMIM ID | 607494 |
| HGNC ID | 6075 |
| Aliases | FLJ12476, MGC131851, MGC149531 |
Description
INPP4B encodes a magnesium-dependent inositol polyphosphate 4-phosphatase that dephosphorylates phosphatidylinositol 3,4-bisphosphate (PI(3,4)P2) to phosphatidylinositol 3-phosphate (PI3P), thereby antagonizing the PI3K/AKT signaling pathway. It functions as a tumor suppressor in multiple cancer types, including breast, prostate, and ovarian cancers. Loss of INPP4B expression is associated with poor prognosis and increased AKT activation.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Breast Cancer | Loss of INPP4B leads to increased PI(3,4)P2 levels and AKT hyperactivation, promoting cell proliferation and survival. | ClinVar, COSMIC |
| Prostate Cancer | Reduced INPP4B expression correlates with PTEN loss and enhanced PI3K signaling. | NCBI Gene, OMIM |
| Ovarian Cancer | INPP4B downregulation is associated with aggressive tumor phenotypes and chemoresistance. | COSMIC, ClinVar |
| Endometrial Cancer | Somatic mutations and copy number loss of INPP4B are observed in endometrial tumors. | COSMIC |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Breast | 10.2 | Medium |
| Prostate | 8.5 | Medium |
| Ovary | 7.1 | Medium |
| Thyroid | 6.8 | Medium |
| Adipose Tissue | 5.3 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| MCF7 (Breast Cancer) | 12.4 | High expression |
| PC3 (Prostate Cancer) | 9.1 | Medium expression |
| OVCAR3 (Ovarian Cancer) | 7.8 | Medium expression |
| HEK293 (Embryonic Kidney) | 6.5 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1063C>T (p.Arg355*) | Nonsense | <1% | Loss of function; truncated protein |
| c.1480_1481del (p.Leu494fs) | Frameshift | <1% | Loss of function; premature stop |
| c.1672G>A (p.Gly558Arg) | Missense | <1% | Unknown functional effect |
Mutation functional classification
Loss of Function (LOF)
Nonsense and frameshift mutations that truncate the protein or disrupt the phosphatase domain, leading to loss of PI(3,4)P2 phosphatase activity.
Gain of Function (GOF)
No gain-of-function mutations have been reported for INPP4B.
Dominant Negative (DN)
No dominant-negative mutations have been described for INPP4B.
View complete mutation data：
Gene Ontology (GO)
| • phosphatidylinositol-3 | • 4-bisphosphate 4-phosphatase activity |
| • phosphatidylinositol phosphate phosphatase activity | • negative regulation of phosphatidylinositol 3-kinase signaling |
| • cellular response to insulin stimulus | • phosphatidylinositol dephosphorylation |
Pathways
• PI3K/AKT signaling pathway
• Phosphatidylinositol phosphate metabolism
• Inositol phosphate metabolism
Protein Summary
INPP4B is a 924-amino acid protein containing a C2 domain and a phosphatase domain. It specifically hydrolyzes the 4-phosphate of phosphatidylinositol 3,4-bisphosphate (PI(3,4)P2) to generate phosphatidylinositol 3-phosphate (PI3P). By reducing PI(3,4)P2 levels, INPP4B attenuates AKT activation and downstream signaling. The protein is localized to the cytoplasm and plasma membrane. Its expression is frequently lost in cancers, contributing to oncogenic PI3K signaling.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| INPP4B Knockout HEK293 Cell Line | EDJ-KQ997 | Human | 8821 | Details Get a Quote |
| INPP4B Knockout A-549 Cell Line | EDJ-KQ20034 | Human | 8821 | Details Get a Quote |
| INPP4B Knockout HCT 116 Cell Line | EDJ-KQ20035 | Human | 8821 | Details Get a Quote |
| INPP4B Knockout HeLa Cell Line | EDJ-KQ20036 | Human | 8821 | Details Get a Quote |
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