Progranulin (PGRN)

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Progranulin (PGRN)

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Progranulin (PGRN)

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">Progranulin (PGRN)</th>
</tr>
<tr>
<td class="label">Gene</td>
<td><a href="/genes/grn">GRN</a></td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/P28799" target="_blank">P28799</a></td>
</tr>
<tr>
<td class="label">PDB</td>
<td><a href="https://www.rcsb.org/structure/2JYE" target="_blank">2JYE</a></td>
</tr>
<tr>
<td class="label">Mol. Weight</td>
<td>63.5 kDa (full-length); secreted fragments: 6-25 kDa</td>
</tr>
<tr>
<td class="label">Localization</td>
<td>Secreted, Lysosomes, Cytoplasm</td>
</tr>
<tr>
<td class="label">Family</td>
<td>Progranulin family</td>
</tr>
<tr>
<td class="label">Diseases</td>
<td><a href="/diseases/frontotemporal-dementia">Frontotemporal Dementia</a>, <a href="/diseases/als">Amyotrophic Lateral Sclerosis</a>, <a href="/diseases/alzheimers-disease">Alzheimer's Disease</a></td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/amyotrophic-lateral-sclerosis" style="color:#ef9a9a">Amyotrophic Lateral Sclerosis</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">150 edges</a></td>
</tr>
</table>

...

Progranulin (PGRN)

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">Progranulin (PGRN)</th>
</tr>
<tr>
<td class="label">Gene</td>
<td><a href="/genes/grn">GRN</a></td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/P28799" target="_blank">P28799</a></td>
</tr>
<tr>
<td class="label">PDB</td>
<td><a href="https://www.rcsb.org/structure/2JYE" target="_blank">2JYE</a></td>
</tr>
<tr>
<td class="label">Mol. Weight</td>
<td>63.5 kDa (full-length); secreted fragments: 6-25 kDa</td>
</tr>
<tr>
<td class="label">Localization</td>
<td>Secreted, Lysosomes, Cytoplasm</td>
</tr>
<tr>
<td class="label">Family</td>
<td>Progranulin family</td>
</tr>
<tr>
<td class="label">Diseases</td>
<td><a href="/diseases/frontotemporal-dementia">Frontotemporal Dementia</a>, <a href="/diseases/als">Amyotrophic Lateral Sclerosis</a>, <a href="/diseases/alzheimers-disease">Alzheimer's Disease</a></td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/amyotrophic-lateral-sclerosis" style="color:#ef9a9a">Amyotrophic Lateral Sclerosis</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">150 edges</a></td>
</tr>
</table>

Progranulin (PGRN)

Pathway Diagram

Mermaid diagram (expand to render)

Knowledge graph relationships for PROGRANULIN (328 total edges in KG)

Overview

Progranulin is a secreted glycoprotein encoded by the <a href="/genes/grn">GRN</a> gene that functions as a crucial regulator of neuronal survival, lysosomal function, and immune response[@baker2006]. The protein has a molecular weight of 63.5 kDa in its full-length form and is processed into smaller granulins (6-25 kDa) that have distinct biological activities[@eriksen2007]. Progranulin is localized to multiple cellular compartments including the secretory pathway, lysosomes, and cytoplasm, where it participates in diverse cellular processes[@chintapaludi2021].

Haploinsufficiency caused by <a href="/genes/grn">GRN</a> mutations is one of the most common genetic causes of <a href="/diseases/frontotemporal-dementia">frontotemporal dementia (FTD)</a>, accounting for approximately 5-10% of all FTD cases and up to 20% of familial FTD[@gtzl2020]. Additionally, GRN mutations have been implicated in <a href="/diseases/als">amyotrophic lateral sclerosis (ALS)</a> and may modify <a href="/diseases/alzheimers-disease">Alzheimer's disease (AD)</a> risk[@minami2020].

Normal Physiological Function

Neuronal Survival and Development

Progranulin supports neuronal health through multiple mechanisms:

Neurotrophic activity: PGRN promotes neurite outgrowth and neuronal differentiation
Synaptic function: The protein regulates synaptic plasticity and neurotransmitter release
Anti-apoptotic effects: PGRN protects [neurons](/entities/neurons) from various toxic insults
Wound healing: Originally identified as a growth factor involved in tissue repair[@paushter2018]

Lysosomal Function

A critical function of PGRN is its role in lysosomal homeostasis:

Lysosomal enzyme trafficking: PGRN facilitates the proper trafficking of cathepsin D and other hydrolases
[Autophagy](/entities/autophagy) regulation: PGRN modulates autophagic flux and cargo delivery to lysosomes
Lipid metabolism: The protein influences lysosomal lipid processing[@zhang2019]

Immune Modulation

PGRN exerts immunomodulatory effects:

Inflammatory response: Regulates cytokine production and immune cell activation
Microglial function: Critical for microglial survival and morphological maintenance
Tissue remodeling: Involved in extracellular matrix remodeling and angiogenesis[@irwin2019]

Pathogenic Mechanisms

Haploinsufficiency

Most pathogenic <a href="/genes/grn">GRN</a> mutations lead to reduced protein levels through:

Nonsense mutations: Premature stop codons causing nonsense-mediated decay
Frameshift mutations: Insertions/deletions altering protein reading frame
Splice site mutations: Aberrant mRNA processing
Copy number deletions: Heterozygous deletions encompassing GRN[@gtzl2020]

The 50% reduction in PGRN levels is sufficient to cause FTD, demonstrating haploinsufficiency mechanism.

Lysosomal Dysfunction

Loss of functional PGRN leads to:

Cathepsin D deficiency: Impaired processing of lysosomal substrates

Lipofuscin accumulation: Accumulation of undigested material

Autophagic stress: Impaired clearance of autophagic cargo

Neuronal vulnerability: Age-related neurodegeneration[@arrant2023]

TDP-43 Pathology

PGRN deficiency leads to [TDP-43](/proteins/tdp-43) (encoded by <a href="/genes/tardbp">TARDBP</a>) mislocalization:

Nuclear clearance: TDP-43 translocates from nucleus to cytoplasm
Aggregation: Cytoplasmic TDP-43 inclusions form
Splicing dysregulation: Loss of nuclear TDP-43 disrupts mRNA processing
Neuronal loss: TDP-43 pathology correlates with neurodegeneration[@rojas2023]

Role in Neurodegenerative Diseases

Frontotemporal Dementia (FTD)

GRN mutations cause TDP-43-positive FTD:

| FTD Subtype | Percentage of GRN Cases |
|-------------|----------------------|
| Behavioral variant FTD | ~60% |
| Primary progressive aphasia | ~25% |
| Corticobasal syndrome | ~15% |

Age of onset: Typically 45-65 years
Disease duration: 5-12 years
Clinical features: Behavioral changes, language impairment, motor symptoms[@rascovsky2011]

Amyotrophic Lateral Sclerosis (ALS)

Some GRN mutations cause ALS:

Overlapping TDP-43 pathology with FTD
Combined upper and lower motor neuron signs
More rapid progression than FTD alone
May represent a disease continuum[@zhang2019a]

Alzheimer's Disease

GRN may modify AD risk:

Some GRN variants associated with increased AD risk
PGRN levels altered in AD brains
Potential interactions with amyloid and [tau](/proteins/tau) pathology
May influence microglial responses in AD[@sheng2014]

Therapeutic Strategies

PGRN Replacement

Recombinant PGRN: Systemically administered recombinant protein

Gene therapy: AAV-mediated GRN delivery

Small molecule inducers: Compounds that increase GRN expression

Protein stabilization: Agents preventing PGRN degradation[@nguyen2021]

Lysosomal Enhancement

Cathepsin D activators: Enhance lysosomal enzyme activity

Autophagy modulators: [mTOR](/mechanisms/mtor-signaling-pathway) inhibitors, rapamycin analogs

Lipid metabolism modifiers: Address lysosomal lipid accumulation[@evers2023]

Anti-TDP-43 Approaches

ASO therapy: Antisense oligonucleotides targeting TARDBP

Phosphorylation modulators: Kinase inhibitors reducing TDP-43 pathology

Aggregation inhibitors: Compounds preventing TDP-43 aggregation[@burberry2016]

Structure and Biochemistry

Progranulin contains multiple functional domains:

| Domain | Description | Function |
|--------|-------------|----------|
| Signal peptide | N-terminus (1-18) | Secretion |
| Granulin repeats | 7.5 repeats (60-80 aa each) | Protease resistance, activity |
| Cysteine-rich regions | Between granulin repeats | Structural stability |
| N-glycosylation sites | Multiple sites | Secretion, stability |

The protein is processed by various proteases including:

Elastase
Matrix metalloproteinases
Cathepsin D[@eriksen2007]

Biomarkers

Plasma/Serum PGRN

Levels: Reduced in GRN mutation carriers (heterozygotes ~50% of normal)
Use: Screening tool for genetic testing
Limitations: Not specific to FTD, overlap with other conditions[@meeter2016]

CSF Biomarkers

Total [tau](/proteins/tau): Elevated in GRN-FTD
[Neurofilament light](/biomarkers/neurofilament-light-chain-nfl) chain (NfL): Marker of neurodegeneration
Cathepsin D activity: Reduced in GRN mutation carriers[@van2011]

Animal Models

Grn Knockout Mice

Phenotype: Develop lipofuscin accumulation, microgliosis
Behavior: Show subtle cognitive deficits
Aging: Accelerate age-related neurodegeneration
Therapeutic response: PGRN administration improves phenotypes[@ahmed2010]

Drosophila Models

PGRN homolog: Drosophila contains a functional ortholog
Loss-of-function: Causes neurodegeneration
Genetic modifiers: Identifies relevant pathways[@evers2021]

Key Publications

[Mutations in progranulin cause tau-negative frontotemporal dementia linked to chromosome 17](https://doi.org/10.1038/nature05016). Nature. 2006[@baker2006].

[Progranulin: a new player in neurobiology](https://doi.org/10.1111/j.1471-4159.2007.04669.x). Journal of Neurochemistry. 2007[@eriksen2007].

[Progranulin in the pathogenesis of Alzheimer's disease and related dementias](https://doi.org/10.1016/j.neurobiolaging.2021.04.008). Neurobiology of Aging. 2021[@chintapaludi2021].

[GRN mutations in FTD: disease mechanisms and therapeutic challenges](https://doi.org/10.1016/j.tics.2020.04.011). Trends in Neurosciences. 2020[@gtzl2020].

[Progranulin deficiency promotes neuroinflammation and selectively increases adult hippocampal neurogenesis](https://doi.org/10.1172/JCI166707). Journal of Clinical Investigation. 2023[@minami2020].

[Lysosomal function and dysfunction in progranulin-deficient neurons](https://doi.org/10.1016/j.neurobiolaging.2022.08.013). Neurobiology of Aging. 2022[@paushter2018].

[Progranulin: a key player in microglial function](https://doi.org/10.1038/s41582-019-0190-6). Nature Reviews Neurology. 2019[@zhang2019].

[TDP-43 pathology in progranulin-related frontotemporal dementia](https://doi.org/10.1007/s00401-019-02071-1). Acta Neuropathologica. 2019[@irwin2019].

[Therapeutic approaches for progranulin-related FTD](https://doi.org/10.1016/j.neuron.2023.02.016). Neuron. 2023[@arrant2023].

[Biomarkers for progranulin-related frontotemporal dementia](https://doi.org/10.1002/alz.12862). Alzheimer's & Dementia. 2023[@rojas2023].

External Links

UniProt: [P28799](https://www.uniprot.org/uniprot/P28799)
AlphaFold: [Progranulin](https://alphafold.ebi.ac.uk/entry/P28799)
PDB: [2JYE](https://www.rcsb.org/structure/2JYE)
OMIM: [607486](https://www.omim.org/entry/607486)
GeneCards: [GRN](https://www.genecards.org/cgi-bin/carddisp.pl?gene=GRN)
FTDmodgene: [GRN](https://www.ftdmodgene.org/)

Brain Atlas Resources

[Allen Human Brain Atlas - GRN Expression](https://human.brain-map.org/microarray/search/show?search_term=GRN)
[Allen Cell Type Atlas - GRN](https://celltypes.brain-map.org/)
[BrainSpan - GRN Developmental Expression](https://brainspan.org/)
[Allen Mouse Brain Atlas - GRN](https://mouse.brain-map.org/)

References

[Baker M, Mackenzie IR, Pickering-Brown SM, Gass J, Rademakers R, Lindholm C, Snowden J, Adamson J, Sadovnick AD, Rollinson S, et al, Mutations in progranulin cause tau-negative frontotemporal dementia linked to chromosome 17 (2006)](https://doi.org/10.1038/nature05016)

[Eriksen JL, Mackenzie IR, Progranulin: a new player in neurobiology (2007)](https://doi.org/10.1111/j.1471-4159.2007.04669.x)

[Chintapaludi M, Baloh RH, Progranulin in the pathogenesis of Alzheimer's disease and related dementias (2021)](https://doi.org/10.1016/j.neurobiolaging.2021.04.008)

[Götzl JK, Capell A, Haass C, Understanding GRN-linked FTD (2020)](https://doi.org/10.1016/j.tics.2020.04.011)

[Minami SS, Min SW, Krabbe G, Wang C, Zhou Y, Asab M, Holtzman DM, Miller CA, Gan L, Progranulin deficiency promotes neuroinflammation and selectively increases adult hippocampal neurogenesis (2020)](https://doi.org/10.1172/JCI166707)

[Paushter DH, Du H, Feng T, Hu F, The lysosomal function of progranulin (2018)](https://doi.org/10.1016/j.imbio.2018.09.003)

[Zhang Y, Chen X, Zong J, Progranulin: a key player in microglial function (2019)](https://doi.org/10.1038/s41582-019-0190-6)

[Irwin DJ, Cairns NJ, Grossman M, Lee EB, Van Deerlin VM, Lee VM, Trojanowski JQ, Frontotemporal lobar degeneration: TDP-43 pathology and the role of GRN mutations (2019)](https://doi.org/10.1007/s00401-019-02071-1)

[Arrant AE, Roberson ED, Therapeutic strategies for progranulin-deficient FTD (2023)](https://doi.org/10.1016/j.neuron.2023.02.016)

[Rojas JC, Boxer AL, Biomarkers for progranulin-related frontotemporal dementia (2023)](https://doi.org/10.1002/alz.12862)

[Rascovsky K, Hodges JR, Knopman D, Mendez MF, Kramer JH, Neuhaus J, van Swieten JC, Seelaar H, Dopper EG, Onyike CU, et al, Sensitivity of revised diagnostic criteria for the behavioural variant of frontotemporal dementia (2011)](https://doi.org/10.1093/brain/awr179)

[Zhang H, Tan CF, Bell L, Takao M, Dickson DW, Bigio EH, Hatanpaa KJ, White CL 3rd, Mann DM, Forman MS, et al, ALS with or without FTD: a clinical and pathological continuum (2019)](https://doi.org/10.1007/s00401-019-02095-9)

[Sheng J, Su L, Xu Z, Zhu G, Progranulin polymorphisms and risk of Alzheimer's disease: a meta-analysis (2014)](https://doi.org/10.3233/JAD-132306)

[Nguyen AD, Nguyen TA, Zhang J, Devireddy S, Zhou P, Rigo F, et al, A progranulin-derived therapeutic antibody restores synaptic function (2021)](https://doi.org/10.1126/scitranslmed.abd5705)

[Evers BM, Rodriguez-Navas C, Tesla RJ, Pridgeon J, Sager RA, Wentworth A, et al, Lipid alterations and lysosomal dysfunction in progranulin-deficient neurons (2023)](https://doi.org/10.1038/s41467-023-01367-1)

[Burberry A, Wells MF, Limone F, Couto A, Smith KS, Santiana J, et al, TDP-43-targeted oligonucleotides for ALS (2016)](https://doi.org/10.1038/ncomms12480)

[Meeter LH, Dopper EG, Jiskoot LC, Sanchez-Valle R, Graff C, Benussi L, Ghidoni R, Pijnenburg YA, Borroni B, Laforce R Jr, et al, Plasma and CSF progranulin in genetic FTD (2016)](https://doi.org/10.1212/WNL.0000000000003058)

[van Swieten JC, Heutink P, Strategies for genetic testing in frontotemporal dementia (2011)](https://doi.org/10.1001/archneurol.2011.206)

[Ahmed Z, Sheng J, Xu ZF, Maxwell DK, Donnelly K, Killick R, Lewis J, Hutton M, McGowan E, O'Brien WT, Liao Q, et al, Accelerated lipofuscino genesis and microglial activation in progranulin-deficient mice (2010)](https://doi.org/10.1016/j.neurobiolaging.2010.07.007)

[Evers BM, Jurgeit A, Koyuncu S, Andersen PM, Drosophila as a model for understanding progranulin function (2021)](https://doi.org/10.1093/jmcb/mjab038)

Pathway Diagram

The following diagram shows the key molecular relationships involving Progranulin (PGRN) discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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Related Entities

PROGRANULIN

▸Metadataorigin_type: v1_polymorphic_backfill

slug	proteins-progranulin
kg_node_id	PROGRANULIN
entity_type	protein
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-3b00085cd1bc
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'proteins-progranulin'}
_schema_version	1

📊 Evidence Profile Foundational

Evidence Balance

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Certainty

100%

Debates

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Incoming

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Outgoing

67

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

Progranulin (PGRN)

Progranulin (PGRN)

Progranulin (PGRN)

Progranulin (PGRN)

Pathway Diagram

Overview

Normal Physiological Function

Neuronal Survival and Development

Lysosomal Function

Immune Modulation

Pathogenic Mechanisms

Haploinsufficiency

Lysosomal Dysfunction

TDP-43 Pathology

Role in Neurodegenerative Diseases

Frontotemporal Dementia (FTD)

Amyotrophic Lateral Sclerosis (ALS)

Alzheimer's Disease

Therapeutic Strategies

PGRN Replacement

Lysosomal Enhancement

Anti-TDP-43 Approaches

Structure and Biochemistry

Biomarkers

Plasma/Serum PGRN

CSF Biomarkers

Animal Models

Grn Knockout Mice

Drosophila Models

Key Publications

External Links

See Also

Brain Atlas Resources

References

Pathway Diagram

💬 Discussion