InterPro: IPR002460 Alpha-synuclein

Synucleins are small, soluble proteins expressed primarily in neural tissue and in certain tumors [1, 2]. The family includes three known proteins: alpha-synuclein, beta-synuclein, and gamma-synuclein. All synucleins have in common a highly conserved alpha-helical lipid-binding motif with similarity to the class-A2 lipid-binding domains of the exchangeable apolipoproteins [3].

Synuclein family members are not found outside vertebrates, although they have some conserved structural similarity with plant 'late-embryo-abundant' proteins. The alpha- and beta-synuclein proteins are found primarily in brain tissue, where they are seen mainly in presynaptic terminals [4, 5]. The gamma-synuclein protein is found primarily in the peripheral nervous system and retina, but its expression in breast tumors [6] is a marker for tumor progression [7]. Normal cellular functions have not been determined for any of the synuclein proteins, although some data suggest a role in the regulation of membrane stability and/or turnover. Mutations in alpha-synuclein are associated with rare familial cases of early-onset Parkinson's disease, and the protein accumulates abnormally in Parkinson's disease, Alzheimer's disease, and several other neurodegenerative illnesses [8].

Synelfin from the zebra finch is a homologue of the human alpha-synuclein and may serve a novel function critical to the regulation of vertebrate neural plasticity [9]. It is regulated during the critical period for song learning.