Intracellular repair of oxidation-damaged alpha-synuclein fails to target C-terminal modification sites

ANDRÉS BINOLFI; ANTONIO LIMATOLA; SILVIA VERZINI; JONAS KOSTEN; FRANCOIS-XAVIER THEILLET; HONOR M. ROSE; BEATA BEKEI; MARCEL STUIVER; MARLEEN VAN ROSSUM; PHILIPP SELENKO

NATURE COMMUNICATIONS

Nature Publishing Group

Lugar: Londres; Año: 2016

2041-1723

Cellular oxidative stress serves as a common denominator in many neurodegenerative disorders, including Parkinson´s disease. Here we use in-cell NMR spectroscopy to study the fate of the oxidation-damaged Parkinson´s disease protein alpha-synuclein (α-Syn) in non-neuronal and neuronal mammalian cells. Specifically, we deliver methionine-oxidized, isotope-enriched α-Syn into cultured cells and follow intracellular protein repair by endogenous enzymes at atomic resolution. We show that N-terminal α-Syn methionines Met1 and Met5 are processed in a stepwise manner, with Met5 being exclusively repaired before Met1. By contrast, C-terminal methionines Met116 and Met127 remain oxidized and are not targeted by cellular enzymes. In turn, persisting oxidative damage in the C-terminus of α-Syn diminishes phosphorylation of Tyr125 by Fyn kinase, which ablates the necessary priming event for Ser129 modification by CK1. These results establish that oxidative stress can lead to the accumulation of chemically and functionally altered α-Syn in cells.