title: Lysine residues at the first and second KTKEGV repeats mediate α-Synuclein binding to membrane phospholipids.
abstract: While α-Synuclein (α-Syn) is mainly detected as a cytosolic protein, a portion of it is recovered bound to membranes. It is suggested that binding to membrane phospholipids controls α-Syn structure, physiology and pathogenesis. We aimed at investigating the role, of the positive charged lysine residues at the KTKEGV repeat motif, in mediating α-Syn associations with membrane phospholipids and in α-Syn oligomerization and aggregation. Specifically, two positive lysine (K) residues were replaced with two negative glutamic acid (E) residues at either the first or second KTKEGV repeat motifs. The effect of these mutations on membrane binding was determined by a quantitative phospholipid ELISA assay and compared to wild-type α-Syn and to the Parkinson's disease-causing mutations, A30P, E46K and A53T. We found that the K to E substitutions affected α-Syn binding to phospholipids. In addition, K to E substitutions resulted in a dramatically lower level of soluble α-Syn oligomers and larger intracellular inclusions. Together, our results suggest a critical role for lysine residues at the N-terminal repeat domain in the pathophysiology of α-Syn.
authors.affiliation: Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel.
authors.forename: Yonaton
authors.initials: Y
authors.lastname: Zarbiv
authors.affiliation: Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel.
authors.forename: Dganit
authors.initials: D
authors.lastname: Simhi-Haham
authors.affiliation: Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel.
authors.forename: Eitan
authors.initials: E
authors.lastname: Israeli
authors.affiliation: Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel.
authors.forename: Suaad Abed
authors.initials: SA
authors.lastname: Elhadi
authors.affiliation: Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel.
authors.forename: Jessica
authors.initials: J
authors.lastname: Grigoletto
authors.affiliation: Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel. Electronic address: ronitsh@ekmd.huji.ac.il.
authors.forename: Ronit
authors.initials: R
authors.lastname: Sharon
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009154:Mutation; D010300:Parkinson Disease / Q000235:genetics; D010743:Phospholipids / Q000378:metabolism*; D051844:alpha-Synuclein / Q000235:genetics* / Q000378:metabolism*
chemical_list: D010743:Phospholipids; C497604:SNCA protein, human; C497605:Snca protein, mouse; D051844:alpha-Synuclein
keywords: Aggregates; KTKEGV repeat; Parkinson's disease; Phospholipids; Soluble α-Syn oligomers; α-Synuclein