Pp2A B55Β Regulatory Subunit is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
| Protein Name | PP2A B55β |
|---|---|
| Gene | PPP2R2B |
| UniProt ID | Q9Y2T7 |
| PDB Structure | 3B7U, 4I0L |
| Molecular Weight | ~46 kDa |
| Subcellular Localization | Cytoplasm, nucleus |
| Protein Family | PP2A B subunit family |
PP2A B55β is a regulatory B subunit of protein phosphatase 2A:
Forms the heterotrimeric PP2A complex:
PP2A B55β-containing complexes dephosphorylate key neuronal substrates:
CAG repeat expansion in PPP2R2B causes SCA12:
Pathogenic Mechanisms:
The PP2A B55β subunit plays a critical role in neuronal health through its substrate specificity. Unlike other B55 isoforms (Bα, Bδ), B55β shows enriched expression in cerebellar and brainstem neurons, which explains the selective vulnerability in SCA12. The regulatory subunit determines substrate selection, and loss of B55β function leads to hyperphosphorylation of specific neuronal proteins including tau, collapsin response mediator proteins (CRMPs), and synaptic receptors.
In Alzheimer's disease, PP2A activity is significantly reduced in the brain, contributing to the accumulation of hyperphosphorylated tau. The B55β-containing PP2A complexes are particularly important for dephosphorylating tau at disease-relevant epitopes. Restoring PP2A activity through B55β modulation represents a potential therapeutic strategy for tauopathies.
PP2A B55β expression and activity in cerebrospinal fluid (CSF) may serve as a biomarker for neurodegenerative diseases:
Current research focuses on:
PP2A B55β represents a critical regulatory hub in neuronal function. Its dysfunction contributes to multiple neurodegenerative diseases, making it an attractive therapeutic target. Ongoing research into isoform-specific modulation holds promise for treating diseases characterized by tau hyperphosphorylation and synaptic dysfunction.
The study of Pp2A B55Β Regulatory Subunit 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.
NeuroWiki - Protein Page | Last Updated: 2026-03-04