PIK3R6 Gene

Introduction

PIK3R6 Gene
Gene Symbol	PIK3R6
Full Name	Phosphoinositide-3-Kinase Regulatory Subunit 6
Aliases	p101, p84, PI3Kgamma
Chromosomal Location	17p13.1
NCBI Gene ID	27137
OMIM	607270
Ensembl ID	ENSG00000110676
UniProt ID	Q9NRA8
KG Connections	1 edges

PIK3R6 (Phosphoinositide-3-Kinase Regulatory Subunit 6) encodes the p101 regulatory subunit of class I phosphoinositide 3-kinases (PI3Ks). While initially characterized in immune cells, emerging research reveals important functions in neuronal survival, synaptic plasticity, and neurodegenerative disease pathogenesis. ^{1Hawkins PT, Stephens LR (2015). PI3K signaling in inflammation and cancer. Biochim Biophys Acta2015 · PMID 25925676Open reference}

Overview

PIK3R6 is located on chromosome 17p13.1 and encodes the p101 (also known as p84) regulatory subunit of PI3K. The gene is catalogued as NCBI Gene ID 27137 and OMIM 607270. p101 forms heterodimers with PI3K catalytic subunits (p110γ) to create functional PI3K complexes that generate phosphatidylinositol-3,4,5-trisphosphate (PIP3). ^{2(2010). PI3K isoforms in cell migration and survival. Nat Rev Cancer2010 · PMID 20190755Open reference}

Gene Information

Protein Structure and Function

PIK3R6 encodes the p101 regulatory subunit:

• SH2 domains: Two src homology 2 domains for phosphotyrosine binding

• iSH2 domain: Inter-SH2 domain for dimerization with catalytic subunit

• p110γ binding: Forms heterodimer with PI3K catalytic subunit p110γ

• Membrane recruitment: Mediates localization to plasma membrane

The p101/p110γ complex is a class IB PI3K predominantly expressed in leukocytes but also detected in neurons and glial cells. ^{3Wymann MP, Marone R (2005). PI3K in disease. Curr Opin Cell Biol2005 · PMID 15821850Open reference}

Normal Physiological Functions

1. PI3K/Akt signaling: Activate downstream Akt pathway promoting cell survival

2. Cell migration: Regulate cytoskeletal dynamics in response to chemoattractants

3. Inflammatory responses: Mediate immune cell activation and cytokine production

4. Neuronal survival: Support neuronal viability through Akt-dependent mechanisms

5. Synaptic plasticity: Regulate synaptic vesicle trafficking and plasticity

Expression Pattern

PIK3R6 shows cell-type specific expression:

• Neurons: Moderate expression in cortical and hippocampal neurons

• Microglia: High expression in activated microglia

• Astrocytes: Detectable expression in astrocytes

• Oligodendrocytes: Low expression in oligodendrocyte lineage cells

• Immune cells: Highest expression in macrophages and neutrophils

Expression data is available from the Allen Human Brain Atlas and Brain RNA-seq. ^{4Allen Human Brain Atlas. PIK3R6 expression dataOpen reference}

Disease Associations

Alzheimer’s Disease

PI3K/Akt signaling is critically involved in AD pathogenesis:

• Amyloid-beta toxicity: PI3K/Akt activation protects neurons from Aβ-induced apoptosis

• Tau phosphorylation: Akt regulates tau kinases (GSK-3β, CDK5) affecting phosphorylation

• Synaptic dysfunction: PI3K signaling regulates synaptic plasticity and memory

• Neuroinflammation: Microglial PI3Kγ contributes to neuroinflammatory responses

• Therapeutic potential: PI3K modulators may protect against AD pathology

Parkinson’s Disease

• Dopaminergic neuron survival: PI3K/Akt pathway supports SNc neuron viability

• Mitophagy: PI3K signaling regulates mitochondrial quality control

• Neuroinflammation: Microglial PI3Kγ promotes neuroinflammation in PD

• LRRK2 interactions: PIK3R6 may interact with LRRK2 pathogenic variants

• Therapeutic targeting: PI3K inhibitors/modulators for PD treatment

Amyotrophic Lateral Sclerosis

• Motor neuron survival: PI3K/Akt promotes motor neuron viability

• Glial activation: Astrocytic and microglial PI3K contributes to neuroinflammation

• Axonal transport: PI3K signaling regulates axonal transport machinery

• Protein aggregation: PI3K dysregulation affects autophagy of protein aggregates

Other Neurological Disorders

• Multiple sclerosis: PI3K in immune cell migration across blood-brain barrier

• Stroke: PI3K/Akt mediates ischemic preconditioning and neuroprotection

• Huntington’s disease: PI3K signaling regulates mutant huntingtin toxicity

• Frontotemporal dementia: PI3K dysregulation in tauopathies

• Psychiatric disorders: PI3K signaling in mood disorders and schizophrenia

Therapeutic Implications

PI3K signaling pathways represent important therapeutic targets:

1. PI3K inhibitors: Isoform-selective inhibitors for neuroinflammation

2. Akt activators: Direct Akt activators for neuroprotection

3. PI3K modulators: Targeting specific cell types (microglia vs. neurons)

4. Combination therapy: PI3K modulators with other disease-modifying approaches

5. Repurposing: FDA-approved PI3K inhibitors for neurodegenerative diseases

Interacting Proteins

PIK3R6 interacts with several key proteins:

• p110γ (PIK3CG): Catalytic subunit of class IB PI3K

• Akt1/PKB: Downstream effector kinase

• GSK-3β: Tau kinase regulated by PI3K/Akt

• mTOR: Downstream regulator of cell growth and autophagy

• PTEN: Negative regulator of PI3K/Akt signaling

Signaling Pathways

PIK3R6 participates in critical signaling cascades:

1. PI3K/Akt/mTOR pathway: Cell survival and growth

2. PI3K/Akt/GSK-3β pathway: Tau phosphorylation

3. PI3K/Akt/NF-κB pathway: Inflammatory gene expression

4. PI3K/Akt/FOXO pathway: Transcription factor regulation

5. PI3K/Akt/Bad pathway: Apoptosis regulation

Research Tools

• Knockout mice: Pik3r6-/- mice show immune cell migration defects

• Conditional KO mice: Cell-type specific deletion for neuronal studies

• Pharmacological tools: PI3K inhibitors (wortmannin, LY294002), Akt inhibitors

• AAV vectors: For neuronal overexpression or knockdown

Summary

PIK3R6 encodes the p101 regulatory subunit of class IB PI3K, which plays essential roles in neuronal survival, synaptic plasticity, and neuroinflammation. PI3K/Akt signaling dysfunction contributes to Alzheimer’s disease, Parkinson’s disease, ALS, and other neurodegenerative disorders. Modulating PIK3R6 and downstream PI3K pathways represents a promising therapeutic strategy for neuroprotection. ^{5(2023). PI3K/Akt signaling in Alzheimer's disease. J Alzheimers Dis2023 · PMID 37249876Open reference}

See Also

• Alzheimer’s Disease

• Parkinson’s Disease

External Links

• Ensembl: ENSG00000110676