Pink1 regulates FKBP5 interaction with AKT/PHLPP and protects neurons from neurotoxin stress induced by MPP

• Published in: Journal of neurochemistry Vol. 150; no. 3; pp. 312 - 329
• Main Authors: Boonying, Wassamon, Joselin, Alvin, Huang, En, Qu, Dianbo, Safarpour, Farzaneh, Iyirhiaro, Grace O., Gonzalez, Yasmilde Rodriguez, Callaghan, Steve M., Slack, Ruth S., Figeys, Daniel, Chung, Young‐Hwa, Park, David S.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.08.2019
• Subjects: 1-Methyl-4-phenylpyridinium - toxicity; AKT; AKT protein; Animals; Brain; Cell Death - drug effects; Death; Degeneration; Embryo fibroblasts; Fibroblasts; FKBP5; HEK293 Cells; Humans; Immunoprecipitation; Kidneys; Kinases; Leucine; Mice; Mice, Knockout; Model testing; Mortality; Movement disorders; MPP; Mutation; Neurodegeneration; Neurodegenerative diseases; Neurons; Neurons - drug effects; Neurons - metabolism; Neurotoxins; Neurotoxins - pharmacology; Parkinson Disease - metabolism; Parkinson's disease; PHLPP; Phosphatase; Phosphoprotein Phosphatases - metabolism; Phosphorylation; Pink1; Protein Kinases - metabolism; Protein phosphatase; Proteins; Proto-Oncogene Proteins c-akt - metabolism; PTEN protein; PTEN-induced putative kinase; Serine; Signal Transduction - physiology; Tacrolimus; Tacrolimus Binding Proteins - metabolism; Toxins; Viruses; AKT; Parkinson's disease; Pink1; PHLPP; phosphorylation; FKBP5
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/jnc.14683

Loss of function mutations in the PTEN‐induced putative kinase 1 (Pink1) gene have been linked with an autosomal recessive familial form of early onset Parkinson's disease (PD). However, the underlying mechanism(s) responsible for degeneration remains elusive. Presently, using co‐immunoprecipitation in HEK (Human embryonic kidney) 293 cells, we show that Pink1 endogenously interacts with FK506‐binding protein 51 (FKBP51 or FKBP5), FKBP5 and directly phosphorylates FKBP5 at Serine in an in vitro kinase assay. Both FKBP5 and Pink1 have been previously associated with protein kinase B (AKT) regulation. We provide evidence using primary cortical cultured neurons from Pink1‐deficient mice that Pink1 increases AKT phosphorylation at Serine 473 (Ser473) challenged by 1‐methyl‐4‐phenylpyridinium (MPP+) and that over‐expression of FKBP5 using an adeno‐associated virus delivery system negatively regulates AKT phosphorylation at Ser473 in murine‐cultured cortical neurons. Interestingly, FKBP5 over‐expression promotes death in response to MPP+ in the absence of Pink1. Conversely, shRNA‐mediated knockdown of FKBP5 in cultured cortical neurons is protective and this effect is reversed with inhibition of AKT signaling. In addition, shRNA down‐regulation of PH domain leucine‐rich repeat protein phosphatase (PHLPP) in Pink1 WT neurons increases neuronal survival, while down‐regulation of PHLPP in Pink1 KO rescues neuronal death in response to MPP+. Finally, using co‐immunoprecipitation, we show that FKBP5 interacts with the kinase AKT and phosphatase PHLPP. This interaction is increased in the absence of Pink1, both in Mouse Embryonic Fibroblasts (MEF) and in mouse brain tissue. Expression of kinase dead Pink1 (K219M) enhances FKBP5 interaction with both AKT and PHLPP. Overall, our results suggest a testable model by which Pink1 could regulate AKT through phosphorylation of FKBP5 and interaction of AKT with PHLPP. Our results suggest a potential mechanism by which PINK1‐FKBP5 pathway contributes to neuronal death in PD. Open Science Badges This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/. Mutations in PD‐associated genes such as Pink1 have been shown to contribute to dysregulation of numerous cellular processes. We identified that Pink1 endogenously interacts with a novel interacting partner FKBP5 and directly phosphorylates it. We provide evidence that Pink1 regulates AKT Ser473 phosphorylation in response to MPP+‐induced mitochondrial stress and FKBP5 negatively regulates this phosphorylation and sensitizes cultured neurons to cell death. Our results suggest a model in which Pink1 regulates AKT through phosphorylation of FKBP5 and its interaction with AKT and PHLPP; a potential mechanism by which Pink1‐FKBP5 pathway may contribute to neuronal death in PD. Open Science: This manuscript was awarded with the Open Materials Badge For more information see: https://cos.io/our-services/open-science-badges/