title: In vivo modulation of polo-like kinases supports a key role for PLK2 in Ser129 α-synuclein phosphorylation in mouse brain.
abstract: α-Synuclein is the major component of Lewy bodies. α-Synuclein phosphorylated at Ser 129 (Phospho-α-Syn) is the most common synuclein modification observed in Parkinson's disease pathology and transgenic animal models. Polo-like kinase 2 (PLK2) was previously proposed as an important kinase in α-synuclein phosphorylation at Ser129. To better understand the role of PLK2 in α-synuclein phosphorylation in vivo, we further evaluated the effect of PLK2 genetic knockdown and pharmacological inhibition on Phospho-α-Syn levels in different brain regions of PLK2 knockout (KO), heterozygous (Het) and wild-type (WT) mice. Whereas PLK2 knockdown had no effect on Total-α-synuclein brain levels, it resulted in a gene-dosage dependent, albeit incomplete, reduction of endogenous Phospho-α-Syn levels in all brain regions investigated. No compensatory induction of other α-synuclein kinases (PLK3, casein kinase-2, G-protein-coupled receptor kinase 5 (GRK5) and GRK6) was observed at the mRNA level in the PLK2 KO mouse brain. To determine whether increased activity of another PLK family member is responsible for the residual Phospho-α-Syn levels in the PLK2 KO mouse brain, the pan-PLK inhibitor BI 2536 was tested in PLK2 KO mice. Whereas BI 2536 reduced Phospho-α-Syn levels in WT mice, it did not further reduce the residual endogenous Phospho-α-Syn levels in PLK2 KO and Het mice, suggesting that a kinase other than PLK1-3 accounts for the remaining PLK inhibitor-resistant pool in the mouse brain. Moreover, PLK3 KO in mice had no effect on both Total- and Phospho-α-Syn brain levels. These results support a significant role for a PLK kinase in phosphorylating α-synuclein at Ser129 in the brain, and suggest that PLK2 is responsible for this activity under physiological conditions.
authors.affiliation: Department of Pharmacological Sciences, Elan Pharmaceuticals, South San Francisco, CA 94080, USA. Electronic address: bergeron.mb@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Bergeron
authors.affiliation: Department of Pharmacological Sciences, Elan Pharmaceuticals, South San Francisco, CA 94080, USA.
authors.forename: R
authors.initials: R
authors.lastname: Motter
authors.affiliation: Department of Pharmacological Sciences, Elan Pharmaceuticals, South San Francisco, CA 94080, USA.
authors.forename: P
authors.initials: P
authors.lastname: Tanaka
authors.affiliation: Department of Pharmacological Sciences, Elan Pharmaceuticals, South San Francisco, CA 94080, USA.
authors.forename: D
authors.initials: D
authors.lastname: Fauss
authors.affiliation: Department of Exploratory Research, Elan Pharmaceuticals, South San Francisco, CA 94080, USA.
authors.forename: M
authors.initials: M
authors.lastname: Babcock
authors.affiliation: Department of Protein Sciences, Elan Pharmaceuticals, South San Francisco, CA 94080, USA.
authors.forename: S-S
authors.initials: SS
authors.lastname: Chiou
authors.affiliation: Department of Protein Sciences, Elan Pharmaceuticals, South San Francisco, CA 94080, USA.
authors.forename: S
authors.initials: S
authors.lastname: Nelson
authors.affiliation: Department of Pharmacological Sciences, Elan Pharmaceuticals, South San Francisco, CA 94080, USA.
authors.forename: F
authors.initials: F
authors.lastname: San Pablo
authors.affiliation: Department of Exploratory Research, Elan Pharmaceuticals, South San Francisco, CA 94080, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Anderson
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D054774:G-Protein-Coupled Receptor Kinase 5 / Q000235:genetics / Q000378:metabolism; D054768:G-Protein-Coupled Receptor Kinases / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D010766:Phosphorylation / Q000187:drug effects / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency / Q000378:metabolism / Q000502:physiology*; D011621:Pteridines / Q000737:chemistry / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D012694:Serine / Q000378:metabolism*; D051844:alpha-Synuclein / Q000235:genetics / Q000378:metabolism*
chemical_list: C518477:BI 2536; D004791:Enzyme Inhibitors; D011621:Pteridines; D012333:RNA, Messenger; D051844:alpha-Synuclein; D012694:Serine; C093328:Plk3 protein, mouse; D017346:Protein Serine-Threonine Kinases; D054774:G-Protein-Coupled Receptor Kinase 5; D054768:G-Protein-Coupled Receptor Kinases; C089176:G-protein-coupled receptor kinase 6; C517895:Grk5 protein, mouse; C444640:serum-inducible kinase
keywords: 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate; ANOVA; BI 2536; CEB; CHAPS; CSNK2a2; Ce; Co; EDTA; EGTA; ELISA; G-protein-coupled receptor kinase; GRK; GusB; HRP; Het; Hi; IV; IgG; IgM; KO; Ob; PBS; PCR; PD; PLK; PLK2; Parkinson’s disease; Phospho-α-Syn; Po; SDS; SNCA; St; TBST; TH; Total-α-Syn; Tris-buffered saline with Tween; VM; WT; alpha prime subunit of casein kinase II; analysis of variance; brain; cell extraction buffer; cerebellum; cerebral cortex; enzyme-linked immunosorbent assay; ethylene glycol tetraacetic acid; ethylenediaminetetraacetic acid; heterozygous; hippocampus; horseradish peroxidase; immunoglobulin G; immunoglobulin M; intravenous; knockout; olfactory bulb; phosphate-buffered saline; phosphorylated α-Synuclein; polo-like kinase; polymerase chain reaction; pons-medulla; qRT-PCR; quantitative real-time reverse-transcription PCR; sodium dodecyl sulfate; striatum; synuclein; thalamus and hypothalamus; total α-synuclein; ventral midbrain; wild-type; α-synuclein mRNA; β-glucuronidase