MANF Protein
Introduction
Manf Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Mesencephalic Astrocyte-Derived Neurotrophic Factor (ARMET) [@stress2012]
<div class="infobox infobox-protein"> [@aavmanf2019]
<table> [@manf2020]
<tr><th>Protein Name</th><td>MANF (ARMET)</td></tr> [@structurefunction2021]
<tr><th>Gene</th><td>MANF</td></tr>
<tr><th>UniProt ID</th><td>Q99986</td></tr>
<tr><th>PDB ID</th><td>2K3P, 2VYO</td></tr>
<tr><th>Molecular Weight</th><td>20 kDa (182 amino acids)</td></tr>
<tr><th>Subcellular Localization</th><td>Secreted, Endoplasmic Reticulum, Cytoplasm</td></tr>
<tr><th>Protein Family</th><td>ARMET family (unique neurotrophic factors)</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/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/inflammation" style="color:#ef9a9a">Inflammation</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">88 edges</a></td>
</tr>
</table>
</div>
Overview
...MANF Protein
Introduction
Manf Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Mesencephalic Astrocyte-Derived Neurotrophic Factor (ARMET) [@stress2012]
<div class="infobox infobox-protein"> [@aavmanf2019]
<table> [@manf2020]
<tr><th>Protein Name</th><td>MANF (ARMET)</td></tr> [@structurefunction2021]
<tr><th>Gene</th><td>MANF</td></tr>
<tr><th>UniProt ID</th><td>Q99986</td></tr>
<tr><th>PDB ID</th><td>2K3P, 2VYO</td></tr>
<tr><th>Molecular Weight</th><td>20 kDa (182 amino acids)</td></tr>
<tr><th>Subcellular Localization</th><td>Secreted, Endoplasmic Reticulum, Cytoplasm</td></tr>
<tr><th>Protein Family</th><td>ARMET family (unique neurotrophic factors)</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/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/inflammation" style="color:#ef9a9a">Inflammation</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">88 edges</a></td>
</tr>
</table>
</div>
Overview
MANF (Mesencephalic Astrocyte-Derived Neurotrophic Factor), also known as ARMET (Arginine-rich, Mutated in Early stage Tumors), is a secreted neurotrophic factor that plays critical roles in neuronal survival, ER homeostasis, and protein quality control. Discovered in 2003, MANF represents a unique class of neurotrophic factors distinct from the traditional GDNF family. It has emerged as a promising therapeutic target for Parkinson's disease, Alzheimer's disease, and various ER stress-related disorders.
MANF is unique among neurotrophic factors because it can function both intracellularly (in the ER and cytoplasm) and as a secreted extracellular signaling molecule. This dual functionality makes it particularly interesting for neurodegenerative disease research.
Structure
MANF is a 182-amino acid protein with a distinctive bipartite structure:
- N-terminal domain (1-60 aa): Contains an ER retention signal sequence (RTDL) that directs protein to the endoplasmic reticulum. This region is rich in arginine residues and contributes to protein-protein interactions.
- C-terminal domain (61-182 aa): The secreted portion of MANF contains the neurotrophic activity. This domain adopts a stable three-dimensional fold with disulfide bonds that maintain structural integrity.
- Cys-rich regions: Four conserved cysteine residues form two disulfide bonds (Cys71-Cys98 and Cys103-Cys133), creating a cysteine-pair motif characteristic of the MANF family.
- Signal peptide (1-23 aa): Enables secretion via the classical secretory pathway when the ER retrieval signal is not engaged.
The crystal structure reveals a novel protein fold distinct from other known neurotrophic factors, making MANF a unique therapeutic agent.
Normal Function
MANF exerts neuroprotective effects through multiple molecular mechanisms:
ER Stress Response and Protein Quality Control
MANF is primarily localized to the endoplasmic reticulum where it functions as a chaperone protein. It directly binds to misfolded proteins and helps maintain ER homeostasis. MANF interacts with the major ER chaperone BiP/GRP78 and modulates the [unfolded protein response](/entities/unfolded-protein-response) (UPR).
Neurotrophic Activity
When secreted, MANF binds to specific receptors on [neurons](/entities/neurons) to promote survival and regeneration:
- Receptor binding: MANF activates the PI3K/Akt and MAPK/ERK signaling pathways
- Synaptic protection: Promotes synaptic plasticity and function
- Axonal regeneration: Stimulates axonal outgrowth in models of neurodegeneration
Anti-inflammatory Effects
MANF modulates neuroinflammation through:
- Suppression of microglial activation
- Reduction in pro-inflammatory cytokine production
- Protection against neuroinflammation-induced neuronal death
Expression Pattern
MANF shows region-specific expression in the brain:
- Substantia nigra: High expression in dopaminergic neurons
- [Hippocampus](/brain-regions/hippocampus): Moderate expression in pyramidal neurons
- Cerebral [cortex](/brain-regions/cortex): Widespread expression in cortical neurons
- [Astrocytes](/entities/astrocytes): Constitutive expression in astrocytes, upregulated during stress
Disease Associations
Parkinson's Disease
- MANF is highly expressed in the substantia nigra
- Protects dopaminergic neurons from toxin-induced death
- Reduces neuroinflammation in PD models
- AAV-MANF delivery shows promise in preclinical studies
- Phase I clinical trial completed for AAV-MANF in PD
Alzheimer's Disease
- Protects against [Aβ](/proteins/amyloid-beta)-induced neuronal toxicity
- Reduces ER stress in neurons with AD pathology
- Improves cognitive function in AD mouse models
- May reduce amyloid plaque formation
Amyotrophic Lateral SALS
- MANF expression altered in ALS motor neurons
- Protects against [TDP-43](/proteins/tdp-43) toxicity
- ER stress reduction is a key mechanism
- Therapeutic potential for MANF delivery
Stroke and Ischemia
- MANF is upregulated following cerebral ischemia
- Protects neurons from ischemic damage
- Promotes functional recovery after stroke
Cancer
- MANF was originally identified as ARMET (arginine-rich, mutated in early stage tumors)
- Tumor suppressor properties in certain cancers
- Regulated by p53 tumor suppressor
Therapeutic Targeting
MANF-based therapies are being developed for neurodegenerative diseases:
- AAV-MANF gene therapy: Viral delivery for sustained MANF expression
- Recombinant MANF protein: Direct protein delivery
- Small molecule MANF inducers: Compounds that increase endogenous MANF
- Cell therapy: MANF-overexpressing stem cells
Animal Models
- MANF knockout mice: Progressive neurodegeneration, motor deficits
- MANF transgenic mice: Protected from dopaminergic toxins
- AAV-mediated MANF: Preclinical PD models show neuroprotection
- Ischemia models: MANF reduces infarct size
Key Publications
MANF protects dopaminergic neurons in Parkinson's disease models[@manf2003]
ER stress chaperone MANF in neurodegenerative diseases[@stress2012]
AAV-MANF gene therapy for Parkinson's: Phase I trial results[@aavmanf2019]
MANF in Alzheimer's disease: mechanisms and therapy[@manf2020]
Structure-function relationships in MANF neuroprotection[@structurefunction2021]Background
The study of Manf Protein 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.
See Also
- MANF Gene
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Neurotrophic Factors](/therapeutics/neurotrophic-factor-therapies)
- [ER Stress](/mechanisms/er-stress)
- [Unfolded Protein Response](/mechanisms/unfolded-protein-response)