in cells with elevated tyrosine kinase activity makes it a candidate oncogene in cancers where such expression is typical. In neurodegenerative diseases Phospholipase D may also play an important pathophysiological role in the progression of neurodegenerative diseases, primarily through its capacity as a signal transducer in indispensable cellular processes like cytoskeletal reorganization and vesicle trafficking. Dysregulation of PLD by the protein α-synuclein has been shown to lead to the specific loss of dopaminergic neurons in mammals. α-synuclein is the primary structural component of Lewy bodies, protein aggregates that are the hallmarks of Parkinson's disease. Disinhibition of PLD by α-synuclein may contribute to Parkinson's deleterious phenotype. Abnormal PLD activity has also been suspected in Alzheimer's disease, where it has been observed to interact with presenilin 1 (PS-1), the principal component of the γ-secretase complex responsible for the enzymatic cleavage of amyloid precursor protein (APP). Extracellular plaques of the product β-amyloid are a defining feature of Alzheimer's diseased brains. Action of PLD1 on PS-1 has been shown to affect the intracellular trafficking of the amyloid precursor to this complex. Phospholipase D3 (PLD3), a non-classical and poorly characterized member of the PLD superfamily, has also been associated with the pathogenesis of this disease. Gallery References External links EC 3.1.4 Peripheral membrane proteins