β-Synuclein (human) (rec.)

Synuclein is a small, soluble protein primarily expressed in neural tissue. The synuclein family includes three known proteins: α-synuclein, β-synuclein, and γ-synuclein. α-Synuclein is a very conserved, small acidic protein (140 residues) with a molecular weight of approximately 19 kDa that accounts for about 1% of total protein in neurons. It is concentrated primarily in presynaptic axon terminals and plays a central role in initiating Parkinson's disease. It is the principal constituent of Lewy bodies which are formed by protein aggregation and inclusion body formation. α-Synuclein lacks secondary or tertiary structure, so it belongs to the family of natively unfolded proteins, many of which act as chaperones. Much of this α-synuclein has been post-translationally modified to increase the rate of oligomerization. Mutant forms of α-Synuclein are associated with autosomal dominant Parkinson's disease. The mutations increase the aggregation rate of the resultant α-synuclein β-Synuclein is found primarily in brain tissue and is seen mainly in presynaptic terminals. It is predominantly expressed in the neocortex, hippocampus, striatum, thalamus, and cerebellum. β-Synuclein may protect the central nervous system from the neurotoxic effects of α-synuclein by inhibiting aggregation of α-synuclein which occurs in neurodegenerative diseases such as Parkinson's disease. γ-Synuclein is a synuclein protein found primarily in the peripheral nervous system (in primary sensory neurons, sympathetic neurons, and motor neurons) and retina. γ-Synuclein expression in breast tumors is a marker for tumor progression.