Interactions of Synphilin-1 with phospholipids and lipid membranes

Synphilin-1 is an alpha-synuclein binding protein that is involved in the pathogenesis of Parkinson's disease. The present study investigated the phospholipid-binding capacity of Synphilin-1. The C-terminus of Synphilin-1 was found to selectively bind to acidic phospholipids, including phosphatidic acid, phosphatidylserine, and phosphatidylglycerol, but not to naturally charged phospholipids. Synphilin-1 was targeted to cytoplasmic lipid droplets in mammalian cells. The amino acid sequence 610-640 was found to represent the primary determinant site for phospholipid binding. Moreover, the R621C mutation identified in Parkinson's disease abolished Synphilin-1 association with lipid droplets. The lipophilicity of Synphilin-1 might prove relevant to its physiologic function.