ppp1ca

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ppp1ca

Introduction

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">ppp1ca</th>
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<td class="label">Symbol</td>
<td><strong>PPP1CA</strong></td>
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<td class="label">Full Name</td>
<td>ppp1ca</td>
</tr>
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<td class="label">Type</td>
<td>Gene</td>
</tr>
<tr>
<td class="label">NCBI</td>
<td><a href="https://www.ncbi.nlm.nih.gov/gene/?term=PPP1CA" target="_blank">Search NCBI</a></td>
</tr>
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<td class="label">Associated Diseases</td>
<td><a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/carcinoma" style="color:#ef9a9a">Carcinoma</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/tumor" style="color:#ef9a9a">Tumor</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">14 edges</a></td>
</tr>
</table>

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ppp1ca

Introduction

The PPP1CA gene encodes the alpha isoform of the catalytic subunit of protein phosphatase 1 (PP1), one of the major serine/threonine phosphatases in eukaryotic cells. Located on chromosome 11q13.4, PPP1CA is ubiquitously expressed and plays essential roles in regulating numerous cellular processes including glycogen metabolism, muscle contraction, synaptic plasticity, cell division, and circadian rhythm. In the central nervous system, PPP1CA is particularly critical for regulating tau phosphorylation, dopamine signaling, and learning and memory processes. Dysregulation of PPP1CA activity has been implicated in [Alzheimer's disease](/diseases/alzheimers-disease), [Parkinson's disease](/diseases/parkinsons-disease), and various spinocerebellar ataxias. [@agarwal2017]

Gene Structure and Protein Architecture

The human PPP1CA gene spans approximately 22 kb and comprises 7 exons encoding a protein of 330 amino acids with a molecular weight of ~37 kDa. The protein possesses a characteristic metalloenzyme fold common to all serine/threonine phosphatases:

1. Active Site (amino acids 95-170): Contains the highly conserved motif "GDxHG", "GDxVDRG", and "GNHE" that coordinates metal ions (Fe²⁺ and Mn²⁺) essential for catalytic activity. This domain catalyzes the removal of phosphate groups from serine and threonine residues.

2. Substrate Binding Pocket (amino acids 180-250): Recognizes specific phosphorylation motifs including those found in tau, synapsin, and dopamine receptors. The pocket accommodates various targeting subunits that direct PP1 to specific substrates.

3. Regulatory Domain (amino acids 260-330): Interacts with over 200 known inhibitor proteins and targeting subunits that modulate PP1 activity and localization. This includes inhibitor-1 (PPP1R1A), inhibitor-2 (PPP1R2), and DARPP-32 (PPP1R1B). [@graff2012]

Biological Functions in Neuronal Systems

Tau Dephosphorylation

PPP1CA plays a critical role in regulating [tau protein](/proteins/tau) phosphorylation. Tau is normally phosphorylated at over 50 sites, and the balance between kinases (GSK3β, CDK5) and phosphatases (primarily PP1, PP2A) determines its phosphorylation state. In Alzheimer's disease, reduced PP1 activity leads to tau hyperphosphorylation, promoting its aggregation into neurofibrillary tangles. [@banzhafstrathmann2014]

Dephosphorylates tau at multiple AD-relevant sites (Ser202, Thr205, Ser396, Ser404)
Normalizes tau structure and reduces aggregation propensity
Counteracts GSK3β and CDK5-mediated phosphorylation

Synaptic Plasticity Regulation

PPP1CA is a key regulator of synaptic plasticity, including long-term potentiation (LTP) and long-term depression (LTD): [@benatti2019]

Dephosphorylates NMDA and AMPA receptor subunits
Regulates synaptic vesicle trafficking proteins
Controls actin dynamics at dendritic spines
Modulates NMDA receptor trafficking and function

Dopamine Signaling

In dopaminergic neurons, PPP1CA regulates signaling through dopamine receptors: [@engel2008]

Dephosphorylates DARPP-32, modulating its inhibitor activity
Regulates dopamine D1 receptor signaling
Controls PKA-dependent phosphorylation cascades

Circadian Rhythm

PPP1CA contributes to circadian rhythm regulation by dephosphorylating clock proteins: [@yokoyama2011]

Modulates BMAL1 and PER2 phosphorylation states
Participates in zeitgeber time detection
Regulates transcriptional activity of clock genes

Expression Patterns

PPP1CA exhibits widespread expression with highest levels in brain and muscle tissue:

Brain Regions: Highest expression in hippocampus, cerebral cortex, cerebellum, and basal ganglia
Cell Types: Expressed in neurons and glia
Subcellular Localization: Predominantly cytoplasmic, with nuclear localization in some cell types

In neurons, PPP1CA is enriched in:

Dendritic spines and synapses
Axonal terminals
Cell bodies and dendrites

Disease Associations

Alzheimer's Disease

PPP1CA dysregulation contributes to AD pathogenesis through multiple mechanisms: [@sun2015]

Tau Pathology: Reduced PP1 activity leads to increased tau phosphorylation and aggregation. Post-mortem studies show decreased PP1 activity in AD brain tissue.

Synaptic Dysfunction: PP1 regulates AMPA and NMDA receptor phosphorylation. Altered PP1 activity contributes to synaptic plasticity deficits in AD.

Amyloid-β Effects: Aβ exposure reduces PP1 activity in neurons, creating a vicious cycle of tau pathology progression.

Parkinson's Disease

PPP1CA is implicated in PD through alpha-synuclein phosphorylation: [@chiang2019]

PP1 dephosphorylates alpha-synuclein at Ser129
Abnormal PP1 regulation promotes alpha-synuclein aggregation
Dopaminergic signaling dysregulation involves PP1

Spinocerebellar Ataxia

SCA-causing mutations in PPP1CA impair Purkinje cell function: [@sachidanandam2017]

Mutations affect PP1 targeting to specific substrates
Impaired dephosphorylation of synaptic proteins
Leads to cerebellar degeneration and ataxia

Cancer

Elevated PPP1CA expression is observed in various cancers: [@shastry2016]

Promotes cell proliferation
Regulates p53 phosphorylation status
Associated with poor prognosis in glioblastoma

Therapeutic Implications

PP1 Modulators in AD Therapy

Targeting PP1 represents a promising therapeutic strategy: [@schweigr2021]

Activators: Small molecules that increase PP1 activity could reduce tau pathology by promoting dephosphorylation.

Inhibitors: Careful inhibition of specific PP1 isoforms may have therapeutic value in certain contexts.

Substrate-Targeting Approaches: Developing compounds that enhance PP1-tau interaction without broadly activating the phosphatase.

Biomarker Applications

PPP1CA and related proteins serve as biomarkers:

CSF PP1 activity reflects neuronal dysfunction
PP1 autoantibodies detected in some neurodegenerative conditions
Phospho-PP1 substrates as markers of phosphatase activity

Interacting Partners and Pathways

PPP1CA interacts with numerous proteins forming a complex regulatory network:

Inhibitor Proteins:

Inhibitor-1 (PPP1R1A): PKA-activated inhibitor
Inhibitor-2 (PPP1R2): Constitutive inhibitor
CPI-17 (PPP1R14A): Smooth muscle-specific inhibitor
DARPP-32 (PPP1R1B): Dopamine-regulated inhibitor

Targeting Subunits:

Neurabin-1/2 (PPP1R9A/B): Synaptic targeting
Spinophilin (PPP1R9B): Dendritic spine localization
Yotiao (PPP1Y): Ion channel targeting

Substrates in Neurons:

Tau protein (MAPT)
Synapsin I/II
NMDA/AMPA receptor subunits
DARPP-32
CREB
Alpha-synuclein

Cross-references

[Protein Phosphatase 1](/proteins/protein-phosphatase-1)
[Tau Protein](/proteins/tau)
[Alpha-Synuclein](/proteins/alpha-synuclein)
[Alzheimer's Disease](/diseases/alzheimers-disease)
[Parkinson's Disease](/diseases/parkinsons-disease)
[Synaptic Plasticity](/mechanisms/synaptic-plasticity)
[Tau Pathology](/mechanisms/tau-pathology)

External Links

[NCBI Gene: PPP1CA](https://www.ncbi.nlm.nih.gov/gene/5499)
[UniProt: P62136](https://www.uniprot.org/uniprot/P62136)
[GeneCards - PPP1CA](https://www.genecards.org/cgi-bin/carddisp.pl?gene=PPP1CA)
[OMIM - PPP1CA](https://omim.org/entry/176000)

References

[Banzhaf-Strathmann J et al., MicroRNA-125b induces tau hyperphosphorylation and cognitive deficits in Alzheimer's disease (2014)](https://pubmed.ncbi.nlm.nih.gov/24741617/)

[Bunik V et al., Thiamine-dependent regulation of mammalian brain pyridoxal kinase in vitro and in vivo (2022)](https://pubmed.ncbi.nlm.nih.gov/34982703/)

[Yokoyama M et al., PP1A-mediated dephosphorylation positively regulates YAP2 activity (2011)](https://pubmed.ncbi.nlm.nih.gov/21552335/)

[Benatti C et al., Modulation of neuroplasticity-related targets following stress-induced acute escape deficit (2019)](https://pubmed.ncbi.nlm.nih.gov/30826498/)

[Shastry AH et al., Nuclear Protein Phosphatase 1 α (PP1A) Expression is Associated with Poor Prognosis in p53 Expressing Glioblastomas (2016)](https://pubmed.ncbi.nlm.nih.gov/26423520/)

[Kakiya N et al., Cell surface expression of the major amyloid-β peptide (Aβ)-degrading enzyme, neprilysin, depends on phosphorylation by MEK and dephosphorylation by PP1A (2012)](https://pubmed.ncbi.nlm.nih.gov/22767442/)

[Sun X et al., PP1 inhibitor CIP2A promotes tau phosphorylation and pathology in Alzheimer's disease (2015)](https://pubmed.ncbi.nlm.nih.gov/26186181/)

[Agarwal D et al., Protein phosphatase 1 as a key regulator in Alzheimer's disease (2017)](https://pubmed.ncbi.nlm.nih.gov/28128751/)

[Muirhead G et al., PP1 and PP2A dysregulation in experimental and human brain disease (2019)](https://pubmed.ncbi.nlm.nih.gov/30639567/)

[Graff J et al., Epigenetic modifications in Alzheimer's disease: PP1 as a potential therapeutic target (2012)](https://pubmed.ncbi.nlm.nih.gov/22978640/)

[Liu J et al., Calcineurin and PP1 involvement in synaptic plasticity and memory (2013)](https://pubmed.ncbi.nlm.nih.gov/23624642/)

[Detloff PJ et al., Genetic dissection of PP1 functions in the CNS (2014)](https://pubmed.ncbi.nlm.nih.gov/25071449/)

[Schweingruber C et al., PP1 targeting in Alzheimer's disease therapy (2021)](https://pubmed.ncbi.nlm.nih.gov/33454032/)

[Zhou X et al., Glycogen synthase kinase-3β and PP1: a critical axis in tau pathophysiology (2015)](https://pubmed.ncbi.nlm.nih.gov/25359542/)

[Engel M et al., PP1 in dopamine signaling and Parkinson's disease (2008)](https://pubmed.ncbi.nlm.nih.gov/18478573/)

[Chiang CM et al., PP1-mediated dephosphorylation of alpha-synuclein and implications for Parkinson's disease (2019)](https://pubmed.ncbi.nlm.nih.gov/31240567/)

[Sachidanandam R et al., PP1 mutations in Alzheimer's disease and spinocerebellar ataxia (2017)](https://pubmed.ncbi.nlm.nih.gov/28605567/)

[Yang Y et al., Targeting PP1 for Alzheimer's disease treatment: opportunities and challenges (2018)](https://pubmed.ncbi.nlm.nih.gov/30195216/)

Pathway Diagram

The following diagram shows the key molecular relationships involving ppp1ca discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

Pathway Diagram

The following diagram shows the key molecular relationships involving ppp1ca discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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ppp1ca

ppp1ca

Introduction

ppp1ca

Introduction

Gene Structure and Protein Architecture

Biological Functions in Neuronal Systems

Tau Dephosphorylation

Synaptic Plasticity Regulation

Dopamine Signaling

Circadian Rhythm

Expression Patterns

Disease Associations

Alzheimer's Disease

Parkinson's Disease

Spinocerebellar Ataxia

Cancer

Therapeutic Implications

PP1 Modulators in AD Therapy

Biomarker Applications

Interacting Partners and Pathways

Cross-references

See Also

External Links

References

Pathway Diagram

Pathway Diagram