title: The novel mechanism of rotenone-induced α-synuclein phosphorylation via reduced protein phosphatase 2A activity.
abstract: Rotenone has been shown to induce many parkinsonian features and has been widely used in chemical models of Parkinson's disease (PD). Its use is closely associated with α-synuclein (α-syn) phosphorylation both in vivo and in vitro. However, the mechanisms whereby rotenone regulates α-syn phosphorylation remain unknown. Protein phosphatase 2A (PP2A) has been shown to play an important role in α-syn dephosphorylation. We therefore investigated if rotenone caused α-syn phosphorylation by down-regulation of PP2A activity in mice. Rotenone increased the phosphorylation of α-syn at Ser129, consistent with the inhibition of PP2A activity by increased phosphorylation of tyrosine 307 at the catalytic subunit of PP2A (pTyr307 PP2Ac). We further explored the interactions among rotenone, PP2A, and α-syn in SK-N-SH cells and primary rat cortical neurons. Rotenone inhibited PP2A activity via phosphorylation of PP2Ac at Tyr307. The reduction in PP2A activity and rotenone cytotoxicity were reversed by treatment with the PP2A agonist, C2 ceramide, and the Src kinase inhibitor, SKI606. Immunoprecipitation experiments showed that rotenone induced an increase in calmodulin-Src complex in SK-N-SH cells, thus activating Src kinase, which in turn phosphorylated PP2A at Tyr307 and inhibited its activity. C2 ceramide and SKI606 significantly reversed the rotenone-induced phosphorylation and aggregation of α-syn by increasing PP2A activity. These results demonstrate that rotenone-reduced PP2A activity via Src kinase is involved in the phosphorylation of α-syn. These findings clarify the novel mechanisms whereby rotenone can induce PD.
authors.affiliation: Department of Neurobiology, Capital Medical University, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, No. 10, XiToutiao outside the YouAnmen, Fengtai District, Beijing 100069, China; Department of Clinical Laboratory, China Rehabilitation Research Center, School of Rehabilitation Medicine, Capital Medical University, No. 10, North Road, Fengtai District, Beijing 100068, China. Electronic address: aprilspring5050@126.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Neurobiology, Capital Medical University, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, No. 10, XiToutiao outside the YouAnmen, Fengtai District, Beijing 100069, China. Electronic address: 562687769@qq.com.
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Neurobiology, Capital Medical University, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, No. 10, XiToutiao outside the YouAnmen, Fengtai District, Beijing 100069, China. Electronic address: chenmin790830@163.com.
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.affiliation: Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, and College of Life Sciences, Beijing Normal University, Beijing 100875, China. Electronic address: dt1098_good@126.com.
authors.forename: Tingting
authors.initials: T
authors.lastname: Du
authors.affiliation: Department of Neurobiology, Capital Medical University, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, No. 10, XiToutiao outside the YouAnmen, Fengtai District, Beijing 100069, China. Electronic address: cldduan@ccmu.edu.cn.
authors.forename: Chunli
authors.initials: C
authors.lastname: Duan
authors.affiliation: Department of Neurobiology, Capital Medical University, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, No. 10, XiToutiao outside the YouAnmen, Fengtai District, Beijing 100069, China. Electronic address: gloria6866@126.com.
authors.forename: Ge
authors.initials: G
authors.lastname: Gao
authors.affiliation: Department of Neurobiology, Capital Medical University, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, No. 10, XiToutiao outside the YouAnmen, Fengtai District, Beijing 100069, China. Electronic address: huiyang@ccmu.edu.cn.
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
mesh_terms: D000818:Animals; D002147:Calmodulin / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D006801:Humans; D008636:Mesencephalon / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010300:Parkinson Disease / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D066329:Protein Aggregates / Q000187:drug effects; D054648:Protein Phosphatase 2 / Q000378:metabolism*; D051381:Rats; D012402:Rotenone / Q000494:pharmacology*; D014443:Tyrosine / Q000378:metabolism; D051844:alpha-Synuclein / Q000737:chemistry / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D002147:Calmodulin; D066329:Protein Aggregates; D051844:alpha-Synuclein; D012402:Rotenone; D014443:Tyrosine; D019061:src-Family Kinases; D054648:Protein Phosphatase 2
keywords: Parkinson’s disease; Phosphorylation; Protein phosphatase 2A; Rotenone; a-Synuclein