PI3K p110α Protein
Introduction
<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">PI3K p110α Protein</th>
</tr>
<tr>
<td class="label">Function</td>
<td>Mechanism</td>
</tr>
<tr>
<td class="label">Synaptic plasticity</td>
<td>CREB activation, AMPA receptor trafficking</td>
</tr>
<tr>
<td class="label">Neuronal survival</td>
<td>Akt-mediated BAD inactivation</td>
</tr>
<tr>
<td class="label">Growth cone guidance</td>
<td>cytoskeletal reorganization</td>
</tr>
<tr>
<td class="label">Metabolism</td>
<td>Glucose uptake regulation</td>
</tr>
<tr>
<td class="label">[Autophagy](/entities/autophagy)</td>
<td>mTORC1 inhibition</td>
</tr>
<tr>
<td class="label">Approach</td>
<td>Agent</td>
</tr>
<tr>
<td class="label">PI3K p110α inhibitors</td>
<td>Various</td>
</tr>
<tr>
<td class="label">Akt activators</td>
<td>SC79, A-443654</td>
</tr>
<tr>
<td class="label">[mTOR](/mechanisms/mtor-signaling-pathway) inhibitors</td>
<td>Rapamycin, Everolimus</td>
</tr>
<tr>
<td class="label">BDNF mimetics</td>
<td>peptide fragments</td>
</tr>
<tr>
<td class="label">Growth factors</td>
<td>BDNF, GDNF</td>
</tr>
<tr>
<td class="label">Biomarker</td>
<td>Sample</td>
</tr>
<tr>
<td class="label">p-Akt (Ser473)</td>
<td>Brain tissue</td>
</tr>
<tr>
<td class="label">p-PI3K</td>
<td>Brain tissue</td>
</tr>
<tr>
<td class="label">PIP3 levels</td>
<td>Brain tissue</td>
</tr>
<tr>
<td class="label">p-mTOR (Ser2448)</td>
<td>Brain tissue</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/amyotrophic-lateral-sclerosis" style="color:#ef9a9a">Amyotrophic Lateral Sclerosis</a>, <a href="/wiki/atherosclerosis" style="color:#ef9a9a">Atherosclerosis</a>, <a href="/wiki/breast-cancer" style="color:#ef9a9a">Breast Cancer</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">443 edges</a></td>
</tr>
</table>
Pi3K P110Α Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
p110α is the catalytic subunit of Class IA PI3K (Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Alpha), encoded by the PIK3CA gene. PI3K is a central signaling molecule in cell growth, survival, and neuronal function. p110α is one of three Class IA catalytic subunits (p110α, p110β, p110δ) and is widely expressed in all tissues, including the brain. It plays critical roles in signal transduction downstream of receptor tyrosine kinases, G-protein coupled receptors, and integrin signaling. Dysregulation of PI3K/Akt signaling is implicated in Alzheimer's disease, Parkinson's disease, and various cancers.
Structure
p110α is a 126.8 kDa protein with multiple functional domains:
- Adapter-binding domain (ABD): Binds to p85 regulatory subunit for membrane localization and activation
- Ras-binding domain (RBD): Couples receptor tyrosine kinase signaling through Ras GTPases
- C2 domain: Mediates membrane phospholipid binding and targeting
- Helical domain: Involved in protein-protein interactions
- Kinase domain: Catalyzes PIP2 phosphorylation to generate PIP3
Structural Features
- P85 binding: Required for stability and membrane recruitment
- Ras activation: Enhances catalytic activity up to 10-fold
- Membrane localization: C2 domain binds phosphatidylinositol lipids
- Hotspot mutations: E545K, H1047R in cancer (not in neurodegeneration)
Normal Function
PI3K Signaling Cascade
Receptor activation: Growth factors (BDNF, NGF, IGF-1) activate RTKs
PI3K recruitment: p85 regulatory subunit binds phosphorylated receptors
PIP3 generation: p110α catalyzes PIP2 → PIP3 conversion
Akt activation: PIP3 recruits Akt to membrane via PH domain
Downstream effects: mTORC1, FOXO, GSK3β phosphorylationKey Functions in Neurons
Brain Region Distribution
- Cortex: High expression in pyramidal neurons
- Hippocampus: CA1-CA3 pyramidal cells, dentate granule cells
- Cerebellum: Purkinje cells, granule cells
- Substantia nigra: Dopaminergic neurons
- Basal forebrain: Cholinergic neurons
Role in Neurodegeneration
Alzheimer's Disease
PI3K/Akt signaling is significantly impaired in Alzheimer's disease, contributing to multiple pathological features:
- Amyloid-β effects: [Aβ](/proteins/amyloid-beta) oligomers inhibit PI3K activity, reducing Akt phosphorylation
- [Tau](/proteins/tau) phosphorylation: Reduced Akt activity leads to increased GSK3β activity and [tau](/proteins/tau) hyperphosphorylation
- Synaptic dysfunction: Impaired PI3K signaling contributes to [LTP](/mechanisms/long-term-potentiation) deficits
- Neuronal survival: Reduced Akt activity increases apoptotic vulnerability
- [mTOR](/entities/mtor) dysregulation: PI3K/Akt/mTOR pathway imbalance affects autophagy
Therapeutic approaches targeting PI3K/Akt in AD include:
- PI3K activators (research phase)
- Akt activators (preclinical)
- BDNF mimetics (experimental)
Parkinson's Disease
PI3K/Akt signaling provides neuroprotection in dopaminergic neurons:
- DA neuron survival: Akt promotes survival of SNpc neurons
- [α-synuclein](/proteins/alpha-synuclein) toxicity: PI3K/Akt mitigates α-syn-induced cell death
- Mitochondrial function: Akt regulates mitochondrial dynamics
- LRRK2 interaction: LRRK2 mutations affect PI3K signaling
Neuroprotective strategies:
- PI3K pathway activation
- Akt phosphorylation enhancement
- Growth factor signaling (GDNF, BDNF)
ALS (Amyotrophic Lateral Sclerosis)
- Motor neuron vulnerability: PI3K/Akt signaling deficits in motor neurons
- Axonal degeneration: Impaired survival signaling
- Therapeutic potential: Enhancing PI3K/Akt may slow progression
Huntington's Disease
- Mutant [huntingtin](/proteins/huntingtin-protein): Interferes with PI3K/Akt signaling
- BDNF transport: Impaired PI3K-dependent axonal transport
- Therapeutic targeting: Restoring PI3K signaling
Therapeutic Targeting
Challenges
- [Blood-brain barrier](/entities/blood-brain-barrier): Poor CNS penetration of most PI3K inhibitors
- Pleiotropic effects: Systemic PI3K inhibition causes metabolic side effects
- Isoform specificity: p110α vs p110β vs p110δ targeting
Biomarkers
Animal Models
Transgenic Models
- PIK3CA knockin mice: Modeling hot-spot mutations
- p85 knockout mice: Lethal embryonically
- Neuron-specific PI3K: Brain-specific effects
Disease Models
- 5xFAD mice: PI3K/Akt pathway deficits
- α-syn transgenic: PI3K protection studies
- mHTT knockin: PI3K signaling restoration
Research Directions
- Blood-brain barrier penetrating PI3K modulators
- Neuron-specific isoform targeting
- Combination therapies (PI3K + other pathways)
- Biomarker development for patient selection
- Gene therapy approaches
See Also
- [PIK3CA Gene](/proteins/pik3ca-protein)
- [PI3K/Akt Signaling Pathway](/mechanisms/pi3k-akt-pathway)
- [mTOR Signaling Pathway](/mechanisms/mtor-neurodegeneration)
- [Autophagy-Lysosomal Pathway](/mechanisms/autophagy-lysosomal-pathway)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
- [Huntington's Disease](/diseases/huntington-disease)
- [Synaptic Dysfunction Pathway](/mechanisms/synaptic-dysfunction-pathway)
- [Neurotrophic Signaling Pathway](/mechanisms/neurotrophic-signaling-pathway)
External Links
- [UniProt: p110α](https://www.uniprot.org/uniprot/P42336)
- [PDB: 2Y3A](https://www.rcsb.org/structure/2Y3A)
- [Human Protein Atlas](https://www.proteinatlas.org/ENSG00000121879-PIK3CA)
- [KEGG Pathway: PI3K-Akt signaling](https://www.kegg.jp/kegg-bin/show_pathway?map=map04151)
Background
The study of Pi3K P110Α Protein 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.
References
<sup>[1]</sup> Cantley LC. The phosphoinositide 3-kinase pathway. Science. 2002;296(5573):1655-1657. PMID: 12040186(https://pubmed.ncbi.nlm.nih.gov/12040186/)
<sup>[2]</sup> Zhou J, et al. The PI3K/Akt signaling pathway in Alzheimer's disease. J Alzheimer's Dis. 2022;86(1):31-44. PMID: 35142679(https://pubmed.ncbi.nlm.nih.gov/35142679/)
<sup>[3]</sup> Han X, et al. PI3K/Akt signaling in Parkinson's disease. Mov Disord. 2021;36(8):1765-1778. PMID: 34041752(https://pubmed.ncbi.nlm.nih.gov/34041752/)
<sup>[4]</sup> Burke JE. Structural basis for regulation of phosphoinositide 3-kinase. Annu Rev Biochem. 2023;92:115-147. PMID: 37133928(https://pubmed.ncbi.nlm.nih.gov/37133928/)
<sup>[5]</sup> Liu Y, et al. Targeting PI3K/Akt signaling for neurodegeneration. Pharmacol Rev. 2024;76(2):245-278. PMID: 38215284(https://pubmed.ncbi.nlm.nih.gov/38215284/)