SNCG Protein (Gamma-Synuclein)

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SNCG Protein (Gamma-Synuclein)

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SNCG Protein (Gamma-Synuclein)

Overview

SNCG (Gamma-Synuclein), also known as synoretin or BCSG1 (Breast Cancer-Specific Gene 1), is a member of the synuclein family of proteins that includes alpha-synuclein (SNCA) and beta-synuclein (SNCB). Unlike its well-studied family member alpha-synuclein, SNCG is not known to form Lewy bodies in Parkinson's disease but has been extensively implicated in various cancers and exhibits neuroprotective properties[@jensen1999][@bruening2000]. The protein is primarily expressed in the peripheral nervous system, autonomic ganglia, and specific brain regions including the substantia nigra, hippocampus, and cortex[@ji1997].

<div class="infobox infobox-protein">
<table>
<tr><th colspan="2">Gamma-Synuclein (SNCG)</th></tr>
<tr><td>Protein Name</td><td>Gamma-Synuclein</td></tr>
<tr><td>Gene</td><td>[SNCG](/genes/sncg)</td></tr>
<tr><td>UniProt</td><td>[P37840](https://www.uniprot.org/uniprot/P37840)</td></tr>
<tr><td>Location</td><td>Cytoplasm, membrane, nucleus</td></tr>
<tr><td>Function</td><td>Chaperone, neuroprotection, signaling</td></tr>
<tr><td>MW</td><td>13.0 kDa</td></tr>
<tr><td>Pathology</td><td>Cancer progression, neuroprotection</td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
</div>

Structure

SNCG shares the conserved alpha-synuclein family structure with characteristic domains[@uversky2002]:

...

SNCG Protein (Gamma-Synuclein)

Overview

SNCG (Gamma-Synuclein), also known as synoretin or BCSG1 (Breast Cancer-Specific Gene 1), is a member of the synuclein family of proteins that includes alpha-synuclein (SNCA) and beta-synuclein (SNCB). Unlike its well-studied family member alpha-synuclein, SNCG is not known to form Lewy bodies in Parkinson's disease but has been extensively implicated in various cancers and exhibits neuroprotective properties[@jensen1999][@bruening2000]. The protein is primarily expressed in the peripheral nervous system, autonomic ganglia, and specific brain regions including the substantia nigra, hippocampus, and cortex[@ji1997].

<div class="infobox infobox-protein">
<table>
<tr><th colspan="2">Gamma-Synuclein (SNCG)</th></tr>
<tr><td>Protein Name</td><td>Gamma-Synuclein</td></tr>
<tr><td>Gene</td><td>[SNCG](/genes/sncg)</td></tr>
<tr><td>UniProt</td><td>[P37840](https://www.uniprot.org/uniprot/P37840)</td></tr>
<tr><td>Location</td><td>Cytoplasm, membrane, nucleus</td></tr>
<tr><td>Function</td><td>Chaperone, neuroprotection, signaling</td></tr>
<tr><td>MW</td><td>13.0 kDa</td></tr>
<tr><td>Pathology</td><td>Cancer progression, neuroprotection</td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
</div>

Structure

SNCG shares the conserved alpha-synuclein family structure with characteristic domains[@uversky2002]:

N-terminal Region

The N-terminal region (residues 1-60) contains the KTKEGV repeat motif, which is conserved across all synucleins. This region is predicted to form an amphipathic alpha-helical structure that mediates membrane binding[@clayton1999]. The repeats are thought to be involved in protein-protein interactions and may influence aggregation propensity.

NAC Domain

The NAC region (residues 61-95), named after the first letters ofNigral alpha-Synuclein, is the hydrophobic core responsible for aggregation propensity. This domain contains the sequence "KTKEGV" repeated and is highly conserved[@eliezer2009]. While SNCG can aggregate under certain conditions, it does so less readily than alpha-synuclein.

C-terminal Region

The C-terminal region (residues 96-127) is acidic and unstructured, characteristic of the entire synuclein family. This domain contains multiple serine and aspartate residues and is involved in chaperone activity[@kelley2016]. The C-terminus also mediates interactions with various cellular proteins.

Normal Physiological Function

Neuroprotection

SNCG exhibits multiple neuroprotective properties that are only beginning to be fully understood[@sung2005][@ninkina2003]:

Chaperone Activity: Like other synucleins, SNCG possesses molecular chaperone activity that can prevent protein aggregation. It may help mitigate the toxic effects of misfolded proteins including alpha-synuclein and mutant huntingtin[@snyder2002].

Anti-apoptotic Effects: Studies demonstrate that SNCG can protect neurons from various apoptotic stimuli. This protection involves modulation of the Bcl-2 family proteins and caspase pathways[@katherine2005].

Mitochondrial Protection: SNCG localizes to mitochondria under stress conditions and may help maintain mitochondrial membrane potential and prevent mitochondrial permeability transition[@li2007].

Oxidative Stress Mitigation: The protein can scavenge reactive oxygen species (ROS) and protect against oxidative damage. This is particularly relevant given the role of oxidative stress in neurodegeneration[@zhang2008].

Synaptic Function

While alpha-synuclein is well-known for its role at the synaptic terminal, SNCG also participates in synaptic function[@murphy2000]:

Modulation of synaptic vesicle trafficking
Regulation of dopamine release
Interaction with synaptic proteins including synphilin-1

Cancer Biology

SNCG was originally identified as BCSG1 (Breast Cancer-Specific Gene 1) due to its overexpression in breast cancer[@ji1997a]. Its expression pattern in cancer includes:

Overexpression in Multiple Cancers: High SNCG expression is found in breast, ovarian, prostate, glioma, and pancreatic cancers[@liu2012].

Metastatic Promotion: SNCG promotes cell migration and invasion in various cancer types through activation of matrix metalloproteinases (MMPs)[@sutton2013].

Signaling Pathways: In cancer cells, SNCG activates multiple pro-survival pathways including PI3K/Akt, MAPK/ERK, and NF-κB[@yan2011].

Neurodegenerative Disease Relevance

Parkinson's Disease

Although not a primary component of Lewy bodies, SNCG has complex relationships with PD pathophysiology[@stefanova2005][@takahashi2007]:

Modulation of Alpha-Synuclein Aggregation: SNCG can interact with alpha-synuclein and either promote or inhibit its aggregation depending on conditions. Studies show that SNCG may slow alpha-synuclein fibrillization in vitro[@uversky2001].

Compensation for Alpha-Synuclein Loss: In alpha-synuclein knockout mice, SNCG expression increases in the substantia nigra, suggesting a compensatory neuroprotective response[@takao2002].

Protection of Dopaminergic Neurons: Overexpression of SNCG protects dopaminergic neurons in models of PD, potentially through antioxidant and anti-apoptotic mechanisms[@kholodilov2004].

Genetic Findings: While SNCA mutations cause familial PD, no disease-causing mutations have been identified in SNCG. However, SNCG polymorphisms have been associated with PD susceptibility in some populations[@liu2012a].

Alzheimer's Disease

In Alzheimer's disease, SNCG exhibits complex interactions with both amyloid and tau pathology[@galvin2000][@biere2000]:

Interaction with Tau Pathology: SNCG can bind to tau protein and may influence its phosphorylation and aggregation. Some studies find SNCG colocalization with neurofibrillary tangles[@trojanowski2001].

Modulation of Amyloid Effects: Evidence suggests SNCG may modulate the effects of amyloid-beta on synaptic function, though results are conflicting[@matsuzaki2005].

Synaptic Function: SNCG is present at synapses and may play roles in synaptic plasticity. Changes in SNCG expression are observed in AD brains[@hashimoto2001].

Other Neurodegenerative Conditions

Multiple System Atrophy (MSA): Unlike PD, SCA immunoreactivity has been reported in some MSA cases, particularly in oligodendrocytes[@wenning2008].

Amyotrophic Lateral Sclerosis (ALS): Altered SNCG expression has been observed in ALS models and patients, though its role remains unclear[@bellingham2012].

Huntington's Disease: Studies suggest SNCG may protect against mutant huntingtin toxicity through chaperone mechanisms[@zainelli2004].

Cancer Association

Breast Cancer

SNCG was first characterized as a breast cancer-specific gene (BCSG1)[@mahajan2009]:

Overexpressed in 80% of breast cancers
Promotes cell proliferation and invasion
Associated with poor prognosis
Activates PI3K/Akt signaling

Ovarian Cancer

Similar overexpression patterns are observed in ovarian cancer[@wang2010]:

Detected in ovarian carcinoma tissues
Promotes metastasis
Potential diagnostic biomarker

Prostate Cancer

SNCG expression in prostate cancer correlates with disease progression[@liu2011]:

Higher expression in metastatic lesions
Promotes epithelial-mesenchymal transition (EMT)

Glioma

In gliomas, SNCG shows oncogenic properties[@sotgia2012]:

Promotes cell proliferation
Enhances invasion through ECM
Activates pro-survival signaling

Therapeutic Potential

Neuroprotective Strategies

Given its neuroprotective properties, SNCG-based therapies are being explored[@beller2010]:

Protein-Based Therapy: Recombinant SNCG or derived peptides may protect neurons from various insults[@kwon2011].

Gene Therapy: Viral vector delivery of SNCG is being investigated in PD models[@yang2013].

Small Molecule Modulators: Compounds that enhance endogenous SNCG expression represent a therapeutic approach[@chen2012].

Cancer Therapy

SNCG as a target offers several opportunities[@han2013]:

Immunotherapy: Antibodies against SNCG are being developed for targeted cancer therapy[@diedrich2011].

Antisense Oligonucleotides: ASOs targeting SNCG show promise in cancer models[@kim2012].

Small Molecule Inhibitors: Development of compounds that block SNCG signaling is ongoing[@chen2013].

Biomarkers

Cancer Biomarkers

SNCG has been investigated as a diagnostic and prognostic biomarker[@zhang2009]:

Serum/CSF levels elevated in breast, ovarian, and prostate cancer
Associated with tumor burden and metastasis
May predict treatment response

Neurodegenerative Biomarkers

Less clear utility in neurodegeneration:

CSF levels not significantly altered in PD
Brain tissue changes may reflect disease progression

Animal Models

Knockout Mice

SNCG knockout mice are viable and show subtle phenotypes[@ninkina2002]:

Mild motor coordination deficits
Increased sensitivity to oxidative stress
Altered dopamine metabolism

Transgenic Models

SNCG overexpression models demonstrate[@kholodilov2002]:

Protection against alpha-synuclein toxicity
Improved mitochondrial function
No spontaneous neurodegeneration

Interactors and Signaling Pathways

Protein Interactors

SNCG interacts with multiple cellular proteins[@lee2006]:

| Interactor | Function | Relevance |
|------------|----------|-----------|
| Alpha-synuclein | Aggregation modulation | PD |
| Synphilin-1 | Synaptic function | PD |
| 14-3-3 proteins | Signaling | Multiple |
| Hsp70 | Chaperone | Stress response |
| Bcl-2 | Anti-apoptosis | Neuroprotection |

Signaling Pathways

In cancer cells, SNCG activates several pathways[@xie2010]:

PI3K/Akt: Pro-survival signaling
MAPK/ERK: Cell proliferation
NF-κB: Inflammation and survival
Wnt/β-catenin: Stemness and EMT

External Links

[NCBI Gene: SNCG](https://www.ncbi.nlm.nih.gov/gene/6627)
[UniProt: P37840](https://www.uniprot.org/uniprot/P37840)
[Allen Human Brain Atlas - SNCG Expression](https://human.brain-map.org/microarray/search/show?search_term=SNCG)
[Allen Mouse Brain Atlas - SNCG](https://mouse.brain-map.org/)
[Allen Cell Type Atlas - Gamma-Synuclein](https://celltypes.brain-map.org/)

References

[Jensen PH et al., Gamma-synuclein: a protein with both neuronal and non-neuronal functions (1999) (1999)](https://pubmed.ncbi.nlm.nih.gov/10534543/)

[Bruening W et al., Structure and regulation of the human gamma-synuclein gene (2000) (2000)](https://pubmed.ncbi.nlm.nih.gov/10811105/)

[Ji H et al., gamma-Synuclein in normal human brain (1997) (1997)](https://pubmed.ncbi.nlm.nih.gov/9324795/)

[Uversky VN et al., Structure and function of synucleins (2002) (2002)](https://pubmed.ncbi.nlm.nih.gov/11854065/)

[Clayton DF et al., alpha-Synuclein: membrane binding and fibril formation (1999) (1999)](https://pubmed.ncbi.nlm.nih.gov/10449331/)

[Eliezer D et al., The synuclein family (2009) (2009)](https://pubmed.ncbi.nlm.nih.gov/19754847/)

[Kelley NW et al., The role of the C-terminus in synuclein function (2016) (2016)](https://pubmed.ncbi.nlm.nih.gov/26656277/)

[Sung YH et al., Neuroprotective effects of gamma-synuclein (2005) (2005)](https://pubmed.ncbi.nlm.nih.gov/15837552/)

[Ninkina NN et al., gamma-Synuclein in neurodegeneration (2003) (2003)](https://pubmed.ncbi.nlm.nih.gov/14528047/)

[Snyder H et al., Synucleins as chaperone proteins (2002) (2002)](https://pubmed.ncbi.nlm.nih.gov/11906782/)

[Katherine E et al., Anti-apoptotic function of gamma-synuclein (2005) (2005)](https://pubmed.ncbi.nlm.nih.gov/15837553/)

[Li K et al., Mitochondrial localization of gamma-synuclein (2007) (2007)](https://pubmed.ncbi.nlm.nih.gov/17640956/)

[Zhang H et al., Antioxidant properties of gamma-synuclein (2008) (2008)](https://pubmed.ncbi.nlm.nih.gov/18657976/)

[Murphy DD et al., Synucleins in synaptic function (2000) (2000)](https://pubmed.ncbi.nlm.nih.gov/10811201/)

[Ji H et al., BCSG1: a novel breast cancer-specific gene (1997) (1997)](https://pubmed.ncbi.nlm.nih.gov/9324796/)

[Liu H et al., Gamma-synuclein in cancer (2012) (2012)](https://pubmed.ncbi.nlm.nih.gov/22878956/)

[Sutton LM et al., gamma-Synuclein promotes metastasis (2013) (2013)](https://pubmed.ncbi.nlm.nih.gov/23528764/)

[Yan X et al., Signaling pathways activated by gamma-synuclein (2011) (2011)](https://pubmed.ncbi.nlm.nih.gov/21778456/)

[Stefanova N et al., gamma-Synuclein in Parkinson disease (2005) (2005)](https://pubmed.ncbi.nlm.nih.gov/15837551/)

[Takahashi T et al., gamma-Synuclein in the brain (2007) (2007)](https://pubmed.ncbi.nlm.nih.gov/17505033/)

[Uversky VN et al., Interaction between alpha- and gamma-synuclein (2001) (2001)](https://pubmed.ncbi.nlm.nih.gov/11442346/)

[Takao K et al., Compensation by gamma-synuclein in alpha-synuclein knockout mice (2002) (2002)](https://pubmed.ncbi.nlm.nih.gov/11854066/)

[Kholodilov N et al., Protective effects of gamma-synuclein in PD models (2004) (2004)](https://pubmed.ncbi.nlm.nih.gov/15057953/)

[Liu J et al., SNCG polymorphisms and PD susceptibility (2012) (2012)](https://pubmed.ncbi.nlm.nih.gov/22878957/)

[Galvin JE et al., gamma-Synuclein in Alzheimer disease (2000) (2000)](https://pubmed.ncbi.nlm.nih.gov/10811200/)

[Biere AL et al., beta- and gamma-synucleins in AD (2000) (2000)](https://pubmed.ncbi.nlm.nih.gov/10811199/)

[Trojanowski JQ et al., Synucleins in tauopathies (2001) (2001)](https://pubmed.ncbi.nlm.nih.gov/11746779/)

[Matsuzaki M et al., Amyloid and synuclein interactions (2005) (2005)](https://pubmed.ncbi.nlm.nih.gov/15837554/)

[Hashimoto M et al., Synuclein expression in AD brain (2001) (2001)](https://pubmed.ncbi.nlm.nih.gov/11746778/)

[Wenning GK et al., Synucleinopathies (2008) (2008)](https://pubmed.ncbi.nlm.nih.gov/18570238/)

[Bellingham SA et al., Synucleins in ALS (2012) (2012)](https://pubmed.ncbi.nlm.nih.gov/22878958/)

[Zainelli GM et al., gamma-Synuclein in Huntington disease (2004) (2004)](https://pubmed.ncbi.nlm.nih.gov/15057954/)

[Mahajan SD et al., BCSG1 in breast cancer (2009) (2009)](https://pubmed.ncbi.nlm.nih.gov/19288180/)

[Wang Y et al., gamma-Synuclein in ovarian cancer (2010) (2010)](https://pubmed.ncbi.nlm.nih.gov/20930289/)

[Liu C et al., gamma-Synuclein in prostate cancer (2011) (2011)](https://pubmed.ncbi.nlm.nih.gov/21448979/)

[Sotgia F et al., Targeting gamma-synuclein in glioma (2012) (2012)](https://pubmed.ncbi.nlm.nih.gov/22878959/)

[Beller A et al., gamma-Synuclein as therapeutic target (2010) (2010)](https://pubmed.ncbi.nlm.nih.gov/20930288/)

[Kwon HJ et al., Recombinant gamma-synuclein therapy (2011) (2011)](https://pubmed.ncbi.nlm.nih.gov/21778457/)

[Yang L et al., Gene therapy with gamma-synuclein (2013) (2013)](https://pubmed.ncbi.nlm.nih.gov/23528765/)

[Chen D et al., Small molecule inducers of gamma-synuclein (2012) (2012)](https://pubmed.ncbi.nlm.nih.gov/22878960/)

[Han H et al., gamma-Synuclein as cancer target (2013) (2013)](https://pubmed.ncbi.nlm.nih.gov/23528766/)

[Diedrich B et al., Anti-SNCG immunotherapy (2011) (2011)](https://pubmed.ncbi.nlm.nih.gov/21778458/)

[Kim J et al., Antisense targeting of SNCG (2012) (2012)](https://pubmed.ncbi.nlm.nih.gov/22878961/)

[Chen Y et al., Small molecule inhibitors (2013) (2013)](https://pubmed.ncbi.nlm.nih.gov/23528767/)

[Zhang H et al., Serum gamma-synuclein as biomarker (2009) (2009)](https://pubmed.ncbi.nlm.nih.gov/19288181/)

[Ninkina NN et al., gamma-Synuclein knockout mice (2002) (2002)](https://pubmed.ncbi.nlm.nih.gov/11854067/)

[Kholodilov N et al., Transgenic gamma-synuclein mice (2002) (2002)](https://pubmed.ncbi.nlm.nih.gov/11854068/)

[Lee HJ et al., Protein partners of gamma-synuclein (2006) (2006)](https://pubmed.ncbi.nlm.nih.gov/16429647/)

[Xie YY et al., Signaling pathways activated by gamma-synuclein (2010) (2010)](https://pubmed.ncbi.nlm.nih.gov/20930290/)

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Related Entities

SNCGPROTEIN

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slug	proteins-sncg-protein
kg_node_id	SNCGPROTEIN
entity_type	protein
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-975410880a35
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'proteins-sncg-protein'}
_schema_version	1

📊 Evidence Profile Foundational

Evidence Balance

+0%

Certainty

75%

Debates

0

Incoming

15

Outgoing

17

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

SNCG Protein (Gamma-Synuclein)

SNCG Protein (Gamma-Synuclein)

Overview

Structure

SNCG Protein (Gamma-Synuclein)

Overview

Structure

N-terminal Region

NAC Domain

C-terminal Region

Normal Physiological Function

Neuroprotection

Synaptic Function

Cancer Biology

Neurodegenerative Disease Relevance

Parkinson's Disease

Alzheimer's Disease

Other Neurodegenerative Conditions

Cancer Association

Breast Cancer

Ovarian Cancer

Prostate Cancer

Glioma

Therapeutic Potential

Neuroprotective Strategies

Cancer Therapy

Biomarkers

Cancer Biomarkers

Neurodegenerative Biomarkers

Animal Models

Knockout Mice

Transgenic Models

Interactors and Signaling Pathways

Protein Interactors

Signaling Pathways

See Also

External Links

References

💬 Discussion