α-synuclein is a member of the synuclein family, the other two proteins being β and γ-synuclein. α-synuclein was originally isolated as a major synaptic vesicle associated protein from the electric organ of the electric fish Torpedo (1). Direct homologues of α-synuclein are found in all vertebrates. Later work connected α-synuclein with human brain pathology, when a protein originally identified as a component of NAC, the “Non-Amyloid beta Component of Alzheimer’s disease amyloid” proved to be a peptide derived from α-synuclein (2). The α-synuclein protein is therefore sometimes known as NAC precursor or NACP.
Further work showed that α-synuclein is a major component of the Lewy bodies of Parkinson’s disease and point mutations of α-synuclein proved to be causative of some forms of familial Parkinson’s disease (3-5). However, despite being discovered as as component of amyloid preparations, α-synuclein is apparently not a major component of the senile plaques of Alzheimer’s disease (6). Early onset Parkinson’s disease may be caused by a duplication or triplication of one of the α-synuclein genes (7, 8). α-synuclein is also found in the Lewy bodies of patients with diffuse Lewy body disease and inclusions in glial cells in the brains of patients with multiple system atrophy (MSA) and amyotrophic lateral sclerosis (ALS).
α-synuclein is heavily expressed in brain and appears to be localized primarily to presynaptic regions, though not with a typical synaptic vesicle distribution pattern. The synuclein proteins appear to have little 3D structure in solution, and probably belong to the family of “intrinsically unstructured proteins” which only adopt a well-defined conformation when bound to other proteins or membrane lipids (9). An excellent recent review of the role of α-synuclein in health and disease was recently published by Mark Cookson (10).
The HGNC name for this protein is SNCA.
His-tagged α-synuclein was run on an SDS-PAGE gel at 2 µg, 1 µg, and 0.5 µg in the indicated lanes. BSA was also run at 2 µg, 1 µg and 0.5 µg as indicated. Left most lane contains Biorad SDS-PAGE protein standards of indicated size. The vector adds an N-terminal His-tag which was used to purify the protein and this, along with some other vector derived sequence, adds about 5 kDa to the molecule. This vector derived sequence can be removed if required.
We generated a cDNA encoding the human α-synuclein and expressed this in E. coli. The vector adds an N-terminal His-tag which was use to purify the protein and this, along with some other vector derived sequence, adds about 5 kDa to the molecule. The construct therefore has a total size of about 20 kDa as shown.
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