| Alpha-Synuclein (α-Syn) | |
|---|---|
| Gene | SNCA |
| UniProt | P37840 |
| PDB | 1XQ8, 2N0A, 6CU7, 6CU8 |
| Mol. Weight | 14.5 kDa |
| Localization | Presynaptic terminals, cytoplasm |
| Family | Synuclein family |
| Diseases | Parkinson's Disease, Dementia with Lewy Bodies, Multiple System Atrophy |
Alpha Synuclein (Α Syn) plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.
Alpha-Synuclein (α-Syn) is a 140-amino acid protein encoded by the SNCA gene that plays a central role in the pathogenesis of Parkinson's disease (PD) and related neurodegenerative disorders known as synucleinopathies[1]. First discovered as the major component of Lewy bodies—the characteristic protein inclusions found in PD brain—alpha-synuclein has become one of the most intensively studied proteins in neurodegeneration research[2].
The protein belongs to the synuclein family, which also includes beta-synuclein (SNCB) and gamma-synuclein (SNCG). Under physiological conditions, alpha-synuclein is primarily located at presynaptic terminals where it regulates synaptic vesicle trafficking and neurotransmitter release. However, in disease states, the protein misfolds and aggregates to form toxic oligomers and insoluble fibrils that accumulate as Lewy bodies and Lewy neurites[3].
Alpha-Synuclein is a natively unstructured protein that can adopt multiple conformational states depending on cellular context and pathological triggers. The protein consists of three distinct domains:
The N-terminal region contains seven imperfect repeats of the motif KTKEGV, which are related to the lipid-binding class A2 amphipathic helices. This region is highly conserved across species and is critical for:
The Non-Aβ Component (NAC) domain is hydrophobic and constitutes the core of the aggregation-prone region. This domain:
The acidic C-terminal tail is highly negatively charged and:
Under physiological conditions, alpha-synuclein performs several important neuronal functions:
Alpha-synuclein is highly enriched at presynaptic terminals where it:
The protein associates with synaptic vesicles through:
Physiological alpha-synuclein may provide:
Recent studies suggest alpha-synuclein can:
The transition from functional protein to toxic aggregate is central to synucleinopathies.
Multiple factors can trigger alpha-synuclein misfolding:
The aggregation process follows a nucleation-dependent mechanism:
Toxic alpha-synuclein species (primarily oligomers) cause neuronal damage through:
Alpha-synuclein is central to PD pathogenesis through multiple mechanisms:
The progression of alpha-synuclein pathology follows a predictable pattern:
This suggests a prion-like propagation from lower brainstem to cortical regions[9].
Multiple therapeutic strategies are being developed:
Active and passive immunization approaches aim to:
Spillantini MG, Schmidt ML, Lee VM, et al. Alpha-synuclein in Lewy bodies. Nature. 1997;388(6645):839-840. PMID:9278044
Polymeropoulos MH, Lavedan C, Leroy E, et al. Mutation in the alpha-synuclein gene identified in families with Parkinson's disease. Science. 1997;276(5321):2045-2047. PMID:9197268
Peelaerts W, Baekelandt V. Alpha-synuclein strains and the variable pathologies of synucleinopathies. Nat Rev Neurol. 2022;18(11):639-652. DOI:10.1038/s41582-022-00690-9
Bussell R Jr, Eliezer D. A structural and functional role for 11-mer repeats in alpha-synuclein. J Mol Biol. 2003;329(4):763-778. PMID:12791826
Fink AL. The aggregation and fibrillation of alpha-synuclein. Acc Chem Res. 2006;39(9):628-634. PMID:16981679
Oueslati A, Ximerakis M, Vekrellis K. Protein aggregation, dysregulation of the ubiquitin-proteasome system and autophagy in the pathogenesis of synucleinopathies. Neurology. 2014;83(14):1279-1289.
Bridi JC, Hirth F. Mechanisms of alpha-synuclein induced synaptopathy in Parkinson's disease. Front Neurosci. 2018;12:80. DOI:10.3389/fnins.2018.00080
Braak H, Del Tredici K, Rüb U, et al. Staging of brain pathology related to sporadic Parkinson's disease. Neurobiol Aging. 2003;24(2):197-211. PMID:12498954
Volc D, Poewe W. Immunotherapy for Parkinson's disease: targeting alpha-synuclein. Nat Rev Neurol. 2022;18(8):455-467.
Alpha Synuclein (Α Syn) plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.
The study of Alpha Synuclein (Α Syn) 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.
In brains with Braak NFT Stage VI, there is a relatively high likelihood of having both TDP-43 and Lewy body pathologies simultaneously in the medial temporal lobe. 61.1% of TDP-43-positive/LB-positive subjects were Braak NFT stage VI compared to 27.9% among those lacking either or both pathologies.
Model System: Human postmortem brain tissue (UK-ADC autopsy cohort)
Statistical Significance: Chi-square test: p=0.004; Two-sample test for proportions: p=0.009
Nelson et al., (2018)
Cases showed: (1) pathology often exists around the periphery of amygdalae near meninges and/or lateral ventricle; (2) peri-amygdaloid grey matter including entorhinal cortex frequently shows pathologies; (3) cortical and transitional regions are vulnerable; (4) phospho-Tau pathology is constant in all aged individuals. Cases 3-6 showed comorbid Ab, Tau, a-synuclein, and TDP-43 pathologies.
Model System: Human postmortem amygdala tissue (UK-ADC autopsy cohort)
Statistical Significance: Not applicable (descriptive case series)
Nelson et al., (2018)
References:
Spillantini MG, Schmidt ML, Lee VM, et al. (1997). "Alpha-synuclein in Lewy bodies." Nature. 388(6645):839-840. ↩︎
Polymeropoulos MH, et al. (1997). "Mutation in the alpha-synuclein gene identified in families with Parkinson's disease." Science. 276(5321):2045-2047. ↩︎
Peelaerts W, Baekelandt V. (2022). "Alpha-synuclein strains and the variable pathologies of synucleinopathies." Nat Rev Neurol. 18(11):639-652. ↩︎
Bussell R Jr, Eliezer D. (2003). "A structural and functional role for 11-mer repeats in alpha-synuclein." J Mol Biol. 329(4):763-778. ↩︎
Fink AL. (2006). "The aggregation and fibrillation of alpha-synuclein." Acc Chem Res. 39(9):628-634. ↩︎
Oueslati A, et al. (2014). "Protein aggregation in synucleinopathies." Neurology. 83(14):1279-1289. ↩︎
Bridi JC, Hirth F. (2018). "Mechanisms of alpha-synuclein induced synaptopathy in Parkinson's disease." Front Neurosci. 12:80. ↩︎
Braak H, et al. (2003). "Staging of brain pathology related to sporadic Parkinson's disease." Neurobiol Aging. 24(2):197-211. ↩︎
Volc D, Poewe W. (2022). "Immunotherapy for Parkinson's disease: targeting alpha-synuclein." Nat Rev Neurol. 18(8):455-467. ↩︎