Physiology, Synuclein

Excerpt

Synucleins are soluble proteins found primarily in nervous system tissue and in specific tumors. There are three families of synuclein: alpha-synuclein, beta-synuclein, and gamma-synuclein. The alpha and beta variants are seen in presynaptic terminals, whereas the gamma variant appears in the peripheral nervous system and retina. The gamma variant is also expressed in breast tumors and serves as a marker for disease progression. Alpha-synuclein is the more studied variant due to its link to Parkinson’s disease, and hence will be the focus of this article.

Alpha-synuclein is the product of the SNCA gene. It is a small protein that occurs in neurons near synaptic vesicles within presynaptic terminals. Recent studies have shown that alpha-synuclein functions in synaptic vesicle recycling, but the exact mechanism is unclear. The protein becomes pathologic when it aggregates and leads to neuron dysfunction, then subsequent cell death.