a member of the synuclein family. Abundantly expressed in the brain. Inhibits phospholipase D2 selectively. May play a role in neuronal plasticity, is abundant in neurofibrillary lesions of Alzheimer's patients. Highly expressed in the substantia nigra of the brain, a region of neuronal degeneration in patients with Parkinson disease. Note: This description may include information from UniProtKB.