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From Proteopedia
CryoEM structure of G51D alpha-synuclein amyloid fibril
Structural highlights
Disease[SYUA_HUMAN] Note=Genetic alterations of SNCA resulting in aberrant polymerization into fibrils, are associated with several neurodegenerative diseases (synucleinopathies). SNCA fibrillar aggregates represent the major non A-beta component of Alzheimer disease amyloid plaque, and a major component of Lewy body inclusions. They are also found within Lewy body (LB)-like intraneuronal inclusions, glial inclusions and axonal spheroids in neurodegeneration with brain iron accumulation type 1. Defects in SNCA are the cause of Parkinson disease type 1 (PARK1) [MIM:168601]. A complex neurodegenerative disorder characterized by bradykinesia, resting tremor, muscular rigidity and postural instability. Additional features are characteristic postural abnormalities, dysautonomia, dystonic cramps, and dementia. The pathology of Parkinson disease involves the loss of dopaminergic neurons in the substantia nigra and the presence of Lewy bodies (intraneuronal accumulations of aggregated proteins), in surviving neurons in various areas of the brain. The disease is progressive and usually manifests after the age of 50 years, although early-onset cases (before 50 years) are known. The majority of the cases are sporadic suggesting a multifactorial etiology based on environmental and genetic factors. However, some patients present with a positive family history for the disease. Familial forms of the disease usually begin at earlier ages and are associated with atypical clinical features.[1] [2] [3] Defects in SNCA are the cause of Parkinson disease type 4 (PARK4) [MIM:605543]. A complex neurodegenerative disorder with manifestations ranging from typical Parkinson disease to dementia with Lewy bodies. Clinical features include parkinsonian symptoms (tremor, rigidity, postural instability and bradykinesia), dementia, diffuse Lewy body pathology, autonomic dysfunction, hallucinations and paranoia. Defects in SNCA are the cause of dementia Lewy body (DLB) [MIM:127750]. A neurodegenerative disorder clinically characterized by mental impairment leading to dementia, parkinsonism, often with fluctuating cognitive function, visual hallucinations, falls, syncopal episodes, and sensitivity to neuroleptic medication. Brainstem or cortical intraneuronal accumulations of aggregated proteins (Lewy bodies) are the only essential pathologic features. Patients may also have hippocampal and neocortical senile plaques, sometimes in sufficient number to fulfill the diagnostic criteria for Alzheimer disease. Function[SYUA_HUMAN] May be involved in the regulation of dopamine release and transport. Induces fibrillization of microtubule-associated protein tau. Reduces neuronal responsiveness to various apoptotic stimuli, leading to a decreased caspase-3 activation. Publication Abstract from PubMedalpha-Synuclein (alpha-Syn) can form different fibril strains with distinct polymorphs and neuropathologies, which is associated with the clinicopathological variability in synucleinopathies. How different alpha-syn fibril strains are produced and selected under disease conditions remains poorly understood. In this study, we show that the hereditary mutation G51D induces alpha-syn to form a distinct fibril strain in vitro. The cryogenic electron microscopy (cryo-EM) structure of the G51D fibril strain was determined at 2.96 A resolution. The G51D fibril displays a relatively small and extended serpentine fold distinct from other alpha-syn fibril structures. Moreover, we show by cryo-EM that wild-type (WT) alpha-syn can assembly into the G51D fibril strain via cross-seeding with G51D fibrils. Our study reveals a distinct structure of G51D fibril strain triggered by G51D mutation but feasibly adopted by both WT and G51D alpha-syn, which suggests the cross-seeding and strain selection of WT and mutant alpha-syn in familial Parkinson's disease (fPD). The hereditary mutation G51D unlocks a distinct fibril strain transmissible to wild-type alpha-synuclein.,Sun Y, Long H, Xia W, Wang K, Zhang X, Sun B, Cao Q, Zhang Y, Dai B, Li D, Liu C Nat Commun. 2021 Oct 29;12(1):6252. doi: 10.1038/s41467-021-26433-2. PMID:34716315[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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