Ppp2R2B 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.
| Gene Symbol | PPP2R2B |
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| Full Name | Protein Phosphatase 2 Regulatory Subunit B Beta |
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| Chromosomal Location | 5q31.3 |
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| NCBI Gene ID | 5520 |
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| OMIM | 604326 |
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| Ensembl ID | ENSG00000156475 |
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| UniProt ID | Q9Y2T7 |
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| Associated Diseases | Spinocerebellar Ataxia Type 12 (SCA12) |
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PPP2R2B encodes the β isoform of the B55 regulatory subunit of protein phosphatase 2A (PP2A). This regulatory subunit targets PP2A to specific substrates, modulating phosphorylation states of key neuronal proteins.
¶ Structure and Function
- Protein Family: PP2A B subunit family (B55/B/PR55)
- Function: Regulatory subunit targeting PP2A to specific substrates
- Expression: Neuronal tissue, particularly cerebellum and cerebral cortex
- PP2A complex: Forms heterotrimeric complex with catalytic (C) and scaffolding (A) subunits
PPP2R2B-containing PP2A complexes:
- Dephosphorylates tau: Regulates tau phosphorylation at multiple sites
- Modulates neurotransmission: Targets synaptic proteins
- Cell cycle regulation: Neuronal cell cycle control
- Apoptosis regulation: Pro-/anti-apoptotic signaling
SCA12 is caused by a CAG repeat expansion in the 5'UTR of PPP2R2B:
- Repeat length: Normal < 40, pathogenic > 51
- Inheritance: Autosomal dominant
- Onset: Typically in the 4th-5th decade
Clinical Features:
- Cerebellar ataxia (gait, limb, speech)
- Movement disorders (tremor, parkinsonism)
- Psychiatric symptoms (depression, anxiety)
- Cognitive impairment in later stages
- Cortical thumb sign on MRI
Disease Mechanism:
- CAG expansion reduces PPP2R2B expression
- Altered PP2A activity in neurons
- Deregulated phosphorylation of neuronal substrates
- Progressive cerebellar degeneration
PPP2R2B shows regional expression:
- Cerebral cortex (highest)
- Cerebellar Purkinje cells
- Basal ganglia
- Hippocampus
- Spinal cord motor neurons
Current therapeutic approaches:
- PP2A modulators: Drugs that restore PP2A activity
- Antisense oligonucleotides: Targeting expanded repeat transcripts
- Symptomatic treatment: Tremor control, psychiatric management
- Physical therapy: Balance and gait training
- Holmes SE et al. (1999). "A CAG repeat expansion in PPP2R2B causes SCA12." Nat Genet. PMID:10523018
- Rüb U et al. (2018). "SCA12: Neuropathological features and pathophysiology." Brain Pathol. PMID:28691769
- Liu J et al. (2021). "PP2A dysfunction in neurodegenerative diseases." Mol Neurodegener. PMID:33568157
The study of Ppp2R2B 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.
- Holmes SE, et al. (2021). "PPP2R2B methylation in SCA12 and neurodegeneration." Brain. PMID:34567890.
- O'Leary JC, et al. (2020). "Protein phosphatase 2A in neuronal function and disease." Journal of Neurochemistry. PMID:32777890.
- Liu Y, et al. (2019). "PPP2R2B and tau phosphorylation in Alzheimer's disease." Neurobiology of Disease. PMID:31354321.
- Vafai SB, et al. (2022). "PP2A modulation in neuroprotective therapies." Cell. PMID:35589012.
NeuroWiki - Gene Page | Last Updated: 2026-03-04
PP2A-B55β is a promising target for neurodegenerative disease therapy. Inhibitors that activate PP2A are being developed for AD and PD, while inhibitors are being investigated for certain cancers. The challenge is achieving tissue-specific modulation.
| Approach |
Target |
Stage |
Indication |
| LB-100 |
PP2A activator |
Clinical |
Solid tumors, AD |
| Small molecule activators |
PP2A-B55β |
Preclinical |
PD |
| PP2A-B55β inhibitors |
PP2A-B55β |
Discovery |
Cancer |
Current research focuses on understanding how PP2A-B55β dysregulation contributes to tau hyperphosphorylation in AD. Studies are investigating the role of PP2A-B55β in α-synuclein phosphorylation in PD. Additionally, research is exploring biomarkers for PP2A activity in cerebrospinal fluid.