Abstract

Although trace levels of phosphorylated α-synuclein (α-syn) are detectable in normal brains, nearly all α-syn accumulated within Lewy bodies in Parkinson disease brains is phosphorylated on serine 129 (Ser-129). The role of the phosphoserine residue and its effects on α-syn structure, function, and intracellular accumulation are poorly understood. Here, co-expression of α-syn and polo-like kinase 2 (PLK2), a kinase that targets Ser-129, was used to generate phosphorylated α-syn for biophysical and biological characterization. Misfolding and fibril formation of phosphorylated α-syn isoforms were detected earlier, although the fibrils remained phosphatase- and protease-sensitive. Membrane binding of α-syn monomers was differentially affected by phosphorylation depending on the Parkinson disease-linked mutation. WT α-syn binding to presynaptic membranes was not affected by phosphorylation, whereas A30P α-syn binding was greatly increased, and A53T α-syn was slightly lower, implicating distal effects of the carboxyl- on amino-terminal membrane binding. Endocytic vesicle-mediated internalization of pre-formed fibrils into non-neuronal cells and dopaminergic neurons matched the efficacy of α-syn membrane binding. Finally, the disruption of internalized vesicle membranes was enhanced by the phosphorylated α-syn isoforms, a potential means for misfolded extracellular or lumenal α-syn to access cytosolic α-syn. Our results suggest that the threshold for vesicle permeabilization is evident even at low levels of α-syn internalization and are relevant to therapeutic strategies to reduce intercellular propagation of α-syn misfolding.

Autore Pugliese

• Pacelli Consiglia

Tutti gli autori

• Samuel F. , Flavin W. P. , Iqbal S. , Pacelli C. , Sri Renganathan Sri D. , Trudeau L.E. , Campbell E.M. , Fraser P.E. , Tandon A.

Titolo volume/Rivista

THE JOURNAL OF BIOLOGICAL CHEMISTRY

Anno di pubblicazione

2016

ISSN

0021-9258

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

Non Disponibile

Numero di citazioni Scopus

14

Ultimo Aggiornamento Citazioni

Non Disponibile

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile