The story of what alpha-synuclein does is still unfoldind. It was discovered in 1988, and is known to be abundant in synaptic terminals. Its function is still unknown, but there is some evidence that it plays a role in synaptic transmission. In 1997, a mutation in alpha-synuclein was discovered in a Greek family, the Contursi kindred, with familial Parkinson disease. This mutation, to my mind, really blew the lid off PD as we knew it. It was qiuckly discovered that antibodies to alpha-synuclein stain Lewy bodies, much more extensively that any other reagents ever applied to human brain tissue.