title: In vitro phosphorylation does not influence the aggregation kinetics of WT α-synuclein in contrast to its phosphorylation mutants.
abstract: The aggregation of alpha-synuclein (α-SYN) into fibrils is characteristic for several neurodegenerative diseases, including Parkinson's disease (PD). Ninety percent of α-SYN deposited in Lewy Bodies, a pathological hallmark of PD, is phosphorylated on serine129. α-SYN can also be phosphorylated on tyrosine125, which is believed to regulate the membrane binding capacity and thus possibly its normal function. A better understanding of the effect of phosphorylation on the aggregation of α-SYN might shed light on its role in the pathogenesis of PD. In this study we compare the aggregation properties of WT α-SYN with the phospho-dead and phospho-mimic mutants S129A, S129D, Y125F and Y125E and in vitro phosphorylated α-SYN using turbidity, thioflavin T and circular dichroism measurements as well as transmission electron microscopy. We show that the mutants S129A and S129D behave similarly compared to wild type (WT) α-SYN, while the mutants Y125F and Y125E fibrillate significantly slower, although all mutants form fibrillar structures similar to the WT protein. In contrast, in vitro phosphorylation of α-SYN on either S129 or Y125 does not significantly affect the fibrillization kinetics. Moreover, FK506 binding proteins (FKBPs), enzymes with peptidyl-prolyl cis-trans isomerase activity, still accelerate the aggregation of phosphorylated α-SYN in vitro, as was shown previously for WT α-SYN. In conclusion, our results illustrate that phosphorylation mutants can display different aggregation properties compared to the more biologically relevant phosphorylated form of α-SYN.
authors.affiliation: Laboratory of Biomolecular Dynamics, KU Leuven, Celestijnenlaan 200G, Leuven B-3001, Belgium. schreurs.sarah@gmail.com.
authors.forename: Sarah
authors.initials: S
authors.lastname: Schreurs
authors.affiliation: Laboratory of Biomolecular Dynamics, KU Leuven, Celestijnenlaan 200G, Leuven B-3001, Belgium. melanie.gerard@kuleuven-kulak.be.
authors.forename: Melanie
authors.initials: M
authors.lastname: Gerard
authors.affiliation: Laboratory of Biomolecular Dynamics, KU Leuven, Celestijnenlaan 200G, Leuven B-3001, Belgium. rita.derua@med.kuleuven.be.
authors.forename: Rita
authors.initials: R
authors.lastname: Derua
authors.affiliation: Laboratory of Biomolecular Dynamics, KU Leuven, Celestijnenlaan 200G, Leuven B-3001, Belgium. etienne.waelkens@med.kuleuven.be.
authors.forename: Etienne
authors.initials: E
authors.lastname: Waelkens
authors.affiliation: Laboratory of Biomolecular Dynamics, KU Leuven, Celestijnenlaan 200G, Leuven B-3001, Belgium. jean-marc.taymans@med.kuleuven.be.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Taymans
authors.affiliation: Laboratory of Biomolecular Dynamics, KU Leuven, Celestijnenlaan 200G, Leuven B-3001, Belgium. veerle.baekelandt@med.kuleuven.be.
authors.forename: Veerle
authors.initials: V
authors.lastname: Baekelandt
authors.affiliation: Laboratory of Biomolecular Dynamics, KU Leuven, Celestijnenlaan 200G, Leuven B-3001, Belgium. yves.engelborghs@fys.kuleuven.be.
authors.forename: Yves
authors.initials: Y
authors.lastname: Engelborghs
mesh_terms: D006801:Humans; D007700:Kinetics; D020125:Mutation, Missense; D010766:Phosphorylation; D058105:Polymerization; D022021:Tacrolimus Binding Proteins / Q000378:metabolism; D051844:alpha-Synuclein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D051844:alpha-Synuclein; D022021:Tacrolimus Binding Proteins