Characterization of α‐synuclein in immune system

Human α‐synuclein is a 140 amino acid protein with little or no secondary structure. α‐Synuclein is expressed at high levels in the brain and enriched in neural synaptic terminals but its physiological function remains largely unknown. More recently, α‐synuclein has been shown to be one of the principal components of Lewy bodies, neuronal inclusions that are found in diverse human neurodegenerative disorder including the Lewy body variant of Alzeheimer's disease, diffuse Lewy body disease, Parkinson's disease, multiple system atrophy. Therefore, α‐synuclein and its abnormal protein aggregation have been thought to play a role in the pathogenesis of these neurodegenerative diseases known as α‐synucleinopathies. In order to understand their etiology and pathogenesis, it is crucial to identify the normal function of ?α‐synuclein. It was previously reported that the splicing variant of ?α‐synuclein is expressed in heart, skeletal muscle, and pancreas. In our study, we identified the expression in spleen and also confirm the expression of α‐synuclein in isolated human lymphocytes. The physiological role in lymphocytes showed relationship with glucocorticoid‐induced apoptosis. This result suggests that the accumulated ?α‐synuclein might be involved in regulation of cell viability by the interaction with signal transduction proteins such as p38 MAP or JNK.