PPP1R15A Gene

PPP1R15A Gene

Overview

PPP1R15A Gene

Overview

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">PPP1R15A Gene</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>PPP1R15A</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>PPP1R15A</td>
</tr>
<tr>
<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=PPP1R15A" target="_blank">Search NCBI</a></td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">46 edges</a></td>
</tr>
</table>

PPP1R15A encodes protein phosphatase 1 regulatory subunit 15A (GADD34), an adaptive stress-response factor that terminates one arm of the [integrated stress response](/mechanisms/integrated-stress-response) by promoting dephosphorylation of eIF2alpha.[@novoa2001][@brush2003] In [neurons](/entities/neurons) and glia, this feedback node helps determine whether acute stress resolves with translational recovery or progresses toward persistent proteostasis failure and cell injury.[@scheper2015][@tsaytler2011]

PPP1R15A is typically low at baseline and strongly inducible by ER stress, amino-acid deprivation, viral response pathways, and DNA damage programs converging on ATF4/CHOP transcriptional signaling.[@novoa2001][@hollien2006] Because [Alzheimer's disease](/diseases/alzheimers-disease), [Parkinson's disease](/diseases/parkinsons-disease), and [amyotrophic lateral sclerosis](/diseases/amyotrophic-lateral-sclerosis) all show sustained proteotoxic and bioenergetic stress signatures, PPP1R15A has become a mechanistically relevant modifier rather than a single-gene disease driver.[@scheper2015][@halliday2015]

Gene And Protein Context

PPP1R15A is located on chromosome 19q13 and encodes a stress-inducible scaffold that recruits catalytic PP1 phosphatase to phospho-eIF2alpha substrates.[@novoa2001][@brush2003] Functionally, PPP1R15A contrasts with its constitutively expressed paralog PPP1R15B (CReP): PPP1R15A is recruited under high-stress conditions, while PPP1R15B sustains tonic baseline dephosphorylation.[@brush2003][@crespillocasado2017]

The core architecture includes:

• An N-terminal stress-responsive region that influences localization and turnover.
• A C-terminal PP1-binding module containing conserved motifs required for holoenzyme assembly and eIF2alpha targeting.[@brush2003][@crespillocasado2017]

Mechanistic Role In Neurodegeneration

Integrated stress response feedback

Under proteotoxic stress, PERK and related kinases increase eIF2alpha phosphorylation, reducing global translation while favoring selective stress transcripts (ATF4, CHOP, and PPP1R15A itself).[@novoa2001][@scheper2015] PPP1R15A-mediated dephosphorylation then restores translational flux. This loop is adaptive if stress is transient, but can become maladaptive when chronic neurodegenerative stress repeatedly reactivates ISR circuits.[@scheper2015][@halliday2015]

Proteostasis and aggregation-prone states

In tauopathy, synucleinopathy, and [TDP-43](/mechanisms/tdp-43-proteinopathy) proteinopathy models, prolonged ISR activity is a recurrent feature. PPP1R15A modulation changes the duration of translational repression and therefore the kinetics of chaperone supply, synaptic protein renewal, and apoptotic signaling thresholds.[@tsaytler2011][@halliday2015][@moreno2012]

Cell-type implications

• Neurons: PPP1R15A may influence synaptic maintenance versus stress-induced dendritic simplification via translational control.[@scheper2015][@halliday2015]
• Glia: microglial and astrocytic stress programs can alter cytokine output and phagocytic state when ISR tone is shifted.[@tsaytler2011][@salminen2009]
• Motor systems: ISR hyperactivation in vulnerable corticospinal and brainstem motor circuits increases interest in PPP1R15A for ALS-spectrum stress biology.[@halliday2015][@moreno2012]

Evidence Landscape By Disease

Alzheimer's disease

Human AD tissue and model systems consistently show ISR activation with elevated p-eIF2alpha and ATF4-related stress transcription. PPP1R15A is best interpreted as a compensatory branch of this axis, with context-dependent net effects.[@scheper2015][@tsaytler2011] Early/intermittent activation may aid recovery; persistent induction may coincide with unstable translational homeostasis and synaptic dysfunction.[@scheper2015][@halliday2015]

Parkinson's disease

Dopaminergic neurons face mitochondrial and proteostatic stress from [alpha-synuclein](/proteins/alpha-synuclein) burden and oxidative load. ISR engagement is documented in several PD-relevant paradigms, and PPP1R15A is a plausible downstream regulator of translation-reset timing rather than a primary pathogenic lesion.[@tsaytler2011][@mercado2016]

ALS/FTD spectrum

ALS and FTD models with TDP-43, SOD1, [C9orf72](/entities/c9orf72), and FUS perturbations show pronounced stress-granule and ISR involvement. PPP1R15A sits at a tractable node where stress adaptation, translational arrest, and degeneration trajectories intersect.[@halliday2015][@moreno2012]

Therapeutic Relevance

Pharmacologic interest in PPP1R15A arises from attempts to rebalance ISR duration:

• Guanabenz/sephin-class concepts: experimental attempts to prolong adaptive eIF2alpha phosphorylation in selected stress states.[@tsaytler2011][@crespillocasado2017]
• ISRIB-class approaches: downstream restoration of translation through eIF2B modulation, functionally intersecting with PPP1R15A-regulated pathways.[@sidrauski2015]
• Pathway strategy: dynamic modulation is likely safer than complete suppression or constitutive activation, because both prolonged arrest and premature translational reactivation can be harmful.[@scheper2015][@halliday2015]

Biomarker And Experimental Priorities

Priority translational readouts include:

• CSF/plasma stress-response panels (ATF4-CHOP-axis complements)
• phospho-eIF2alpha and downstream translational signatures in patient-derived cells
• multimodal correlation with neuroinflammation and synaptic injury biomarkers

See Also

• [integrated stress response](/mechanisms/integrated-stress-response)
• [Alzheimer's disease](/diseases/alzheimers-disease)
• [Parkinson's disease](/diseases/parkinsons-disease)
• [amyotrophic lateral sclerosis](/diseases/amyotrophic-lateral-sclerosis)
• [ER stress](/mechanisms/er-stress-pathway)mechanisms/er-stress-neurodegeneration)

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
• [KEGG Pathways](https://www.genome.jp/kegg/pathway.html)

References

Pathway Diagram

The following diagram shows the key molecular relationships involving PPP1R15A Gene discovered through SciDEX knowledge graph analysis:

Expression Profile

Sources: [GTEx Portal v10](https://gtexportal.org/home/gene/ppp1r15a) | [Allen Brain Atlas](https://www.brain-map.org/)

GTEx Tissue Expression (median TPM)

| Rank | Tissue | Median TPM |
|------|--------|------------|
| 1 | Lung | 255.78 |
| 2 | Adipose Visceral Omentum | 227.56 |
| 3 | Nerve Tibial | 210.78 |
| 4 | Artery Aorta | 203.42 |
| 5 | Skin Not Sun Exposed Suprapubic | 194.88 |
| 6 | Fallopian Tube | 174.59 |
| 7 | Artery Tibial | 161.69 |
| 8 | Skin Sun Exposed Lower leg | 157.55 |
| 9 | Whole Blood | 156.84 |
| 10 | Artery Coronary | 156.39 |
| 11 | Uterus | 151.16 |
| 12 | Adipose Subcutaneous | 146.33 |
| 13 | Bladder | 139.05 |
| 14 | Ovary | 130.06 |
| 15 | Vagina | 125.13 |

Highest expression outside brain: Lung (255.78 TPM)