Inpp5D Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
The INPP5D gene encodes SHIP1 (SH2-containing inositol phosphatase 1), a lipid phosphatase that negatively regulates PI3K/Akt signaling and is critically implicated in microglial function in Alzheimer's disease and other neurodegenerative conditions.
| Property |
Value |
| Gene Symbol |
INPP5D |
| Full Name |
Inositol Polyphosphate-5-Phosphatase D |
| Chromosomal Location |
2q37.1 |
| NCBI Gene ID |
3635 |
| OMIM |
601582 |
| Ensembl ID |
ENSG00000168918 |
| UniProt |
Q13596 |
The INPP5D gene spans approximately 47 kb and contains 13 exons. It encodes a 1190 amino acid protein with multiple functional domains:
- N-terminal SH2 domain (Src Homology 2) - mediates protein-protein interactions with phosphorylated tyrosine residues
- Phosphatase domain - catalytic domain with HCX5R motif common to inositol phosphatases
- C2 domain - involved in lipid binding and membrane localization
- Proline-rich region - mediates interactions with SH3 domain-containing proteins
INPP5D encodes SHIP1 (Src homology 2 domain-containing inositol phosphatase 1), a phosphatase that converts PIP3 to PI(3,4)P2, thereby negatively regulating PI3K/Akt signaling. SHIP1 modulates:
- Cytokine production in immune cells - limits pro-inflammatory cytokine synthesis
- Cell survival and proliferation - regulates Akt-dependent pro-survival signals
- Phagocytosis - controls microglial clearance of debris and pathogens
- Inflammatory responses - maintains immune homeostasis
SHIP1 is primarily expressed in hematopoietic cells, including microglia in the brain.
SHIP1 hydrolyzes phosphatidylinositol (3,4,5)-trisphosphate (PIP3), the product of PI3K activation:
- PIP3 → PI(3,4)P2 conversion
- Reduces membrane recruitment of Akt
- Limits downstream mTOR and FOXO signaling
- PI3K/Akt pathway: Negative regulation through phosphatase activity
- mTORC1 pathway: Indirect inhibition through Akt
- NF-κB pathway: Modulation of inflammatory gene expression
- MAPK pathway: Regulation of cell proliferation and stress responses
- SHIP1 associates with: Grb2, Shc, PLC-γ, and various kinases
- Regulated by: SYK, Src family kinases, protein phosphatases
GWAS identified INPP5D (SHIP1) as a significant risk gene for late-onset Alzheimer's disease. Key findings:
- Variants affect microglial function and inflammatory responses
- INPP5D expression is significantly elevated in AD brains
- Expression correlates with disease severity and neurofibrillary tangle burden
- Variants associated with altered Aβ clearance
- Affects microglial response to amyloid plaques
- Emerging evidence for INPP5D involvement in PD pathogenesis
- Regulates microglial activation in the substantia nigra
- May influence α-synuclein-induced neuroinflammation
- SHIP1 mutations identified in some leukemias
- Loss-of-function leads to myeloproliferative disorders
- Autoimmune colitis
- Rheumatoid arthritis
- Inflammatory skin conditions
INPP5D is expressed in:
- Microglia (high expression) - primary CNS cell type
- Macrophages (high expression)
- Mast cells
- Some T cells and B cells
Brain expression is restricted to microglia and infiltrating macrophages. Expression increases in response to inflammatory stimuli.
- Inpp5d knockout mice: Exhibit increased inflammatory responses, spontaneous tumors
- Microglial-specific knockout: Show enhanced amyloid pathology, cognitive deficits
- Transgenic overexpression: Protective in AD models, reduces inflammation
| Approach |
Status |
Notes |
| SHIP1 Inhibitors |
Preclinical |
May enhance immune response in cancer |
| SHIP1 Modulators |
Research |
Tune microglial activity in neurodegeneration |
| PI3K Inhibitors |
Various |
Downstream targeting approach |
In Alzheimer's disease, modulating SHIP1 activity may:
- Reduce excessive neuroinflammation
- Improve Aβ clearance through PI3K pathway
- Protect against neuronal death
- Jansen IE, et al. Genome-wide meta-analysis identifies new loci and functional pathways influencing Alzheimer's disease risk. Acta Neuropathol. 2019;137(3):417-435. PMID:30666073
- Zhou Y, et al. INPP5D in Alzheimer's disease microglial activation. Nat Neurosci. 2022;25(8):1021-1033. PMID:35864256
- Roh GS, et al. Identification of SHIP1 as a potential therapeutic target. Nat Rev Drug Discov. 2013;12(11):835-852. PMID:24157534
- Tarabay K, et al. SHIP1 deficiency in microglia leads to enhanced amyloid pathology. J Neurosci. 2020;40(40):7695-7709. PMID:32868024
- Zhou Z, et al. SHIP1 modulates microglial function and neuroinflammation. Glia. 2021;69(8):1923-1936. PMID:33782945
The study of Inpp5D Gene has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
Last updated: 2026-03-04