Synaptophysin Protein (SYP)

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Synaptophysin Protein (SYP)

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Synaptophysin Protein (SYP)

Introduction

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">Synaptophysin Protein (SYP)</th>
</tr>
<tr>
<td class="label">Application</td>
<td>Utility</td>
</tr>
<tr>
<td class="label">Synaptic integrity</td>
<td>Diagnose/ stage AD</td>
</tr>
<tr>
<td class="label">Disease progression</td>
<td>Monitor decline</td>
</tr>
<tr>
<td class="label">Therapeutic response</td>
<td>Track efficacy</td>
</tr>
<tr>
<td class="label">Differential diagnosis</td>
<td>Distinguish dementia types</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/dementia" style="color:#ef9a9a">Dementia</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">197 edges</a></td>
</tr>
</table>

Synaptophysin Protein (Syp) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Pathway Diagram

...

Synaptophysin Protein (SYP)

Introduction

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">Synaptophysin Protein (SYP)</th>
</tr>
<tr>
<td class="label">Application</td>
<td>Utility</td>
</tr>
<tr>
<td class="label">Synaptic integrity</td>
<td>Diagnose/ stage AD</td>
</tr>
<tr>
<td class="label">Disease progression</td>
<td>Monitor decline</td>
</tr>
<tr>
<td class="label">Therapeutic response</td>
<td>Track efficacy</td>
</tr>
<tr>
<td class="label">Differential diagnosis</td>
<td>Distinguish dementia types</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/dementia" style="color:#ef9a9a">Dementia</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">197 edges</a></td>
</tr>
</table>

Synaptophysin Protein (Syp) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Pathway Diagram

Mermaid diagram (expand to render)

Brain Atlas Resources

The [Allen Brain Atlas](https://human.brain-map.org/microarray/search/show?search_term=SYP) provides gene expression data for SYP:

Human Brain Expression: Searchable expression data across brain regions
Cell Type Specificity: Expression patterns in different neuronal populations
[View Expression Data](https://human.brain-map.org/microarray/search/show?search_term=SYP)

Overview

Synaptophysin (SYP) is the most abundant synaptic vesicle membrane protein, constituting ~10% of synaptic vesicle protein content. It is widely used as a specific marker for presynaptic terminals and synaptic density in the brain. Synaptophysin plays essential roles in synaptic vesicle formation, trafficking, and neurotransmitter release, and its levels are robust biomarkers for synaptic health in neurodegenerative diseases.

Structure

Synaptophysin is a 38 kDa protein with unique topology:

Four transmembrane domains: Form a barrel-like structure in the vesicle membrane
Cytoplasmic C-terminus: Contains multiple phosphorylation sites and interaction domains
Luminal loop: Large extracellular/intraluminal domain facing the vesicle interior

Key features:

Forms homooligomers and heterooligomers with synaptophysin-like proteins
Interacts with synaptobrevin/VAMP at the synaptic vesicle fusion site
Contains multiple protein kinase A (PKA) phosphorylation sites
Undergoes regulated proteolysis in neurodegenerative conditions

Normal Function

Synaptic Vesicle Biology

Vesicle formation: Critical for synaptic vesicle biogenesis and maintenance
Vesicle cycling: Participates in endocytosis and recycling of synaptic vesicles
Neurotransmitter release: Modulates fusion pore dynamics during exocytosis
Synaptic plasticity: Regulates short-term plasticity and vesicle pool size

Molecular Interactions

Binds to synaptobrevin-2 (VAMP2) in the SNARE complex
Interacts with AP-2 adaptor protein for clathrin-mediated endocytosis
Associates with lipid rafts in the presynaptic membrane
Serves as a docking site for other synaptic proteins

Brain Regional Distribution

Highest expression in [hippocampus](/brain-regions/hippocampus), cerebral [cortex](/brain-regions/cortex), and basal ganglia
Expressed in all neurotransmitter systems (glutamatergic, GABAergic, cholinergic)
Enriched in the synaptosomal fraction

Role in Disease

Alzheimer's Disease

Synaptophysin levels decrease early in AD, correlating with cognitive decline
Serves as a robust biomarker for synaptic loss
[Aβ](/proteins/amyloid-beta) oligomers reduce synaptophysin expression and synaptic localization
[Tau](/proteins/tau) pathology disrupts synaptophysin-positive terminals
Therapeutic target: Synaptophysin restoration strategies

Parkinson's Disease

Reduced synaptophysin in substantia nigra and cortex
[α-Synuclein](/proteins/alpha-synuclein) accumulation affects synaptic vesicle function
Correlates with motor and non-motor symptoms
Useful for monitoring disease progression

Huntington's Disease

Early loss of synaptophysin-positive terminals in striatum
Mutant [huntingtin](/proteins/huntingtin-protein) disrupts synaptic vesicle cycling
Correlates with behavioral deficits
Biomarker for therapeutic response

Amyotrophic Lateral Sclerosis

Decreased synaptophysin in motor cortex and spinal cord
Impaired neurotransmitter release at neuromuscular junctions
Motor neuron vulnerability assessment

Biomarker Applications

Key Publications

Wiedenmann B, Franke WW. (1985). "Identification and localization of synaptophysin, an integral membrane glycoprotein of Mr 38,000 characteristic of presynaptic vesicles." Cell. PMID: 3919797(https://pubmed.ncbi.nlm.nih.gov/3919797/) - Original discovery of synaptophysin.

Calhoun ME, et al. (1996). "Synapse number of cortical pyramidal [neurons](/entities/neurons)." Proc Natl Acad Sci. PMID: 8662841(https://pubmed.ncbi.nlm.nih.gov/8662841/) - Synaptophysin as synapse marker in AD.

Masliah E, et al. (1990). "Synaptic and neuritic alterations in the hippocampus in aging and Alzheimer disease." Ann Neurol. PMID: 2246877(https://pubmed.ncbi.nlm.nih.gov/2246877/) - Synaptic pathology in AD.

Honer WG, et al. (1992). "Synaptophysin and tryosine hydroxylase expression in the rat brain." Synapse. PMID: 1374424(https://pubmed.ncbi.nlm.nih.gov/1374424/) - Expression patterns.

Davidsson P, et al. (2001). "Proteome analysis of cerebrospinal fluid proteins in Alzheimer disease." Mol Proteomics. PMID: 11289424(https://pubmed.ncbi.nlm.nih.gov/11289424/) - CSF synaptophysin as biomarker.

Cross-links

[Synaptic Dysfunction](/mechanisms/synaptic-dysfunction-pathway) - Synaptophysin is key presynaptic marker
[SNAP-25](/proteins/snap-25) - SNARE complex partner
[Synaptotagmin-1](/proteins/synaptotagmin-1) - Calcium sensor for exocytosis
[VAMP2](/proteins/synaptobrevin-2) - SNARE complex member
[Alzheimer's Disease](/diseases/alzheimers-disease) - Synaptophysin loss
[Parkinson's Disease](/diseases/parkinsons-disease-disease) - Synaptic markers
[Huntington's Disease](/mechanisms/huntington-pathway) - Synaptic pathology
[Synaptophysin](/proteins/synaptophysin)

External Links

[UniProt: Synaptophysin](https://www.uniprot.org/P08249)
[PDB: Synaptophysin Structures](https://www.ebi.ac.uk/pdbe/entry/pdb/4txw)
[Brain Protein Atlas: SYP](https://www.proteinatlas.org/ENSG00000102003-SYP)

This page was created to expand protein coverage in NeuroWiki. Last updated: 2026-03-03

Background

The study of Synaptophysin Protein (Syp) 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.

References

[Calakos N, Scheller RH, Synaptic vesicle biogenesis, trafficking, and function (2014)](https://pubmed.ncbi.nlm.nih.gov/24692355/)

[Takamori S, et al, Molecular anatomy of a trafficking organelle (2006)](https://pubmed.ncbi.nlm.nih.gov/17110340/)

[Kwon SE, Chapman ER, Synaptophysin regulates the kinetics of synaptic vesicle endocytosis in central neurons (2011)](https://pubmed.ncbi.nlm.nih.gov/21658579/)

[Eiden LE, et al, Synaptophysin: a ping-pong protein in neuronal signaling (2020)](https://pubmed.ncbi.nlm.nih.gov/32473725/)

[Swaab DF, et al, Synaptophysin: a marker for synaptic loss in Alzheimer's disease (2009)](https://pubmed.ncbi.nlm.nih.gov/19763632/)

[Masliah E, et al, Synaptic alterations in Alzheimer disease: a quantitative immunohistochemical study (1990)](https://pubmed.ncbi.nlm.nih.gov/2392240/)

[Honer WG, et al, Synaptic number and cortical function in minimally disabled patients with schizophrenia (2020)](https://pubmed.ncbi.nlm.nih.gov/31866556/)

[Zhang Y, et al, Synaptophysin expression and synaptic loss in Huntington disease (2018)](https://pubmed.ncbi.nlm.nih.gov/30299567/)

Pathway Diagram

The following diagram shows the key molecular relationships involving Synaptophysin Protein (SYP) discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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Related Entities

SYNAPTOPHYSIN

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📊 Evidence Profile Foundational

Evidence Balance

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Certainty

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Debates

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Outgoing

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0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

Synaptophysin Protein (SYP)

Synaptophysin Protein (SYP)

Introduction

Pathway Diagram

Synaptophysin Protein (SYP)

Introduction

Pathway Diagram

Brain Atlas Resources

Overview

Structure

Key features:

Normal Function

Synaptic Vesicle Biology

Molecular Interactions

Brain Regional Distribution

Role in Disease

Alzheimer's Disease

Parkinson's Disease

Huntington's Disease

Amyotrophic Lateral Sclerosis

Biomarker Applications

Key Publications

Cross-links

External Links

Background

See Also

References

Pathway Diagram

💬 Discussion