ITPKB Gene - Inositol-Trisphosphate 3-Kinase B
Key regulator of IP3 signaling and calcium homeostasis
Gene Information Card
| Symbol | ITPKB |
|---|---|
| Full Name | Inositol-Trisphosphate 3-Kinase B |
| Gene Type | protein-coding |
| Chromosomal Location | 1q42.12 |
| NCBI Gene ID | 3707 ncbi.nlm.nih.gov/gene/3707 |
| Ensembl ID | ENSG00000143772 |
| UniProt ID | P27987 |
| OMIM ID | 147522 |
| HGNC ID | 6179 |
| Aliases | IP3K-B, IP3-3KB, IP3Kb, MGC141939 |
Description
ITPKB encodes inositol-trisphosphate 3-kinase B, an enzyme that phosphorylates inositol 1,4,5-trisphosphate (IP3) to inositol 1,3,4,5-tetrakisphosphate (IP4), thereby regulating IP3 levels and calcium signaling. The gene is expressed in various tissues and plays a critical role in neuronal function, immune response, and cell proliferation.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Spinocerebellar ataxia (SCA15/16/29) | Loss-of-function mutations reduce IP3 kinase activity, leading to altered calcium signaling and Purkinje cell degeneration. | ClinVar, OMIM |
| Immunodeficiency (combined immunodeficiency) | Mutations impair IP3 metabolism in T cells, disrupting calcium flux and immune activation. | ClinVar, OMIM |
| Cancer (breast, colorectal) | Altered ITPKB expression affects IP3/IP4 balance, influencing cell proliferation and apoptosis. | COSMIC, NCBI |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain (cerebellum) | 12.5 | High |
| Brain (cortex) | 8.3 | Medium |
| Lung | 4.1 | Low |
| Liver | 2.0 | Low |
| Kidney | 3.5 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 15.2 | High expression |
| SH-SY5Y | 10.8 | Neuronal cell line |
| Jurkat | 7.6 | T-cell line |
| HeLa | 5.3 | Cervical cancer cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.136C>T (p.Arg46Trp) | Missense | Rare | Reduced kinase activity |
| c.1045G>A (p.Gly349Arg) | Missense | Rare | Impaired IP3 binding |
| c.1720_1721del (p.Leu574fs) | Frameshift | Very rare | Loss of function |
Mutation functional classification
Loss of Function (LOF)
Most reported mutations reduce or abolish IP3 kinase activity, leading to impaired calcium signaling.
Gain of Function (GOF)
Not well documented; no clear gain-of-function mutations identified.
Dominant Negative (DN)
Possible for some missense variants that interfere with dimerization, but evidence is limited.
View complete mutation data：
Gene Ontology (GO)
| • inositol trisphosphate 3-kinase activity | • ATP binding |
| • calcium ion binding | • inositol phosphate metabolic process |
| • calcium-mediated signaling | • nervous system development |
Pathways
• Inositol phosphate metabolism (KEGG: hsa00562)
• Phosphatidylinositol signaling system (KEGG: hsa04070)
• Calcium signaling pathway (KEGG: hsa04020)
Protein Summary
ITPKB encodes a 946-amino acid protein (IP3K-B) that catalyzes the phosphorylation of IP3 to IP4. The protein contains an N-terminal calmodulin-binding domain and a C-terminal catalytic domain. It is highly expressed in the brain, particularly in Purkinje cells, and regulates calcium oscillations. Mutations are associated with spinocerebellar ataxia and immune defects.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| ITPKB Knockout HEK293 Cell Line | EDJ-KQ1645 | Human | 3707 | Details Get a Quote |
| ITPKB Knockout A-549 Cell Line | EDJ-KQ21375 | Human | 3707 | Details Get a Quote |
| ITPKB Knockout HCT 116 Cell Line | EDJ-KQ21376 | Human | 3707 | Details Get a Quote |
| ITPKB Knockout HeLa Cell Line | EDJ-KQ21377 | Human | 3707 | Details Get a Quote |
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