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Rab10 Phosphorylation Detection by LRRK2 Activity Using SDS-PAGE with a Phosphate-binding Tag
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Rab10 Phosphorylation Detection by LRRK2 Activity Using SDS-PAGE with a Phosphate-binding Tag

Published on: December 14, 2017

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PPM1H phosphatase counteracts LRRK2 signaling by selectively dephosphorylating Rab proteins

Kerryn Berndsen1, Pawel Lis1, Wondwossen M Yeshaw2

  • 1MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom.

Elife
|October 31, 2019
PubMed

Insights

Protein phosphatase PPM1H dephosphorylates Rab proteins, counteracting LRRK2 signaling implicated in Parkinson's disease. Enhancing PPM1H activity may offer new therapeutic strategies for Parkinson's disease.

Area of Science:

  • Neuroscience
  • Cell Biology
  • Biochemistry

Background:

  • Mutations in Leucine-rich repeat kinase 2 (LRRK2) are a common cause of Parkinson's disease.
  • LRRK2 phosphorylates Rab GTPases, affecting their interactions with downstream effectors.
  • The dephosphorylation mechanisms counteracting LRRK2 signaling remain largely uncharacterized.

Purpose of the Study:

  • To identify protein phosphatases that regulate LRRK2 signaling.
  • To investigate the role of PPM1H in modulating LRRK2-mediated Rab phosphorylation.
  • To explore PPM1H as a potential therapeutic target for Parkinson's disease.

Main Methods:

  • siRNA screening of human protein phosphatases.
  • Cellular assays in A549 cells to assess Rab phosphorylation levels.
  • Biochemical studies using purified proteins and a substrate-trapping mutant of PPM1H.
  • Immunofluorescence to determine PPM1H localization and effect on primary cilia.

Main Results:

  • PPM1H was identified as a novel negative regulator of LRRK2 signaling.
  • PPM1H specifically dephosphorylates LRRK2-phosphorylated Rab proteins, including Rab8A.
  • PPM1H knockout enhanced Rab phosphorylation, while its overexpression suppressed it.
  • PPM1H knockdown impaired primary cilia formation, mirroring effects of pathogenic LRRK2.

Conclusions:

  • PPM1H acts as a key phosphatase counteracting LRRK2 activity by dephosphorylating Rab proteins.
  • PPM1H's function in regulating Rab phosphorylation and primary cilia formation highlights its importance in cellular homeostasis.
  • Modulating PPM1H activity presents a promising therapeutic avenue for Parkinson's disease.
Keywords:
LRRK2Parkinson's diseaseRab GTPasebiochemistrycell signallingchemical biologyhumanmouseprotein kinaseprotein phosphatase

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