S-Nitrosylation of G protein-coupled receptor kinase 6 and Casein kinase 2 alpha modulates their kinase activity toward alpha-synuclein phosphorylation in an animal model of Parkinson's disease.

Kenny K K Chung,Stephan N Witt,Weiwei Wu,Jiahua Li,Chun Chau Sung,Peichun Yu

doi:10.1371/journal.pone.0232019

Kenny K K Chung, Stephan N Witt + Show 4 more

Open Access

https://doi.org/10.1371/journal.pone.0232019

Copy DOI

Abstract

Parkinson’s disease (PD) is a common neurodegenerative disorder which is mostly sporadic but familial-linked PD (FPD) cases have also been found. The first reported gene mutation that linked to PD is α-synuclein (α-syn). Studies have shown that mutations, increased expression or abnormal processing of α-syn can contribute to PD, but it is believed that multiple mechanisms are involved. One of the contributing factors is post-translational modification (PTM), such as phosphorylation of α-syn at serine 129 by G-protein-coupled receptor kinases (GRKs) and casein kinase 2α (CK2α). Another known important contributing factor to PD pathogenesis is oxidative and nitrosative stress. In this study, we found that GRK6 and CK2α can be S-nitrosylated by nitric oxide (NO) both in vitro and in vivo. S-nitrosylation of GRK6 and CK2α enhanced their kinase activity towards the phosphorylation of α-syn at S129. In an A53T α-syn transgenic mouse model of PD, we found that increased GRK6 and CK2α S-nitrosylation were observed in an age dependent manner and it was associated with an increased level of pSer129 α-syn. Treatment of A53T α-syn transgenic mice with Nω-Nitro-L-arginine (L-NNA) significantly reduced the S-nitrosylation of GRK6 and CK2α in the brain. Finally, deletion of neuronal nitric oxide synthase (nNOS) in A53T α-syn transgenic mice reduced the levels of pSer129 α-syn and α-syn in an age dependent manner. Our results provide a novel mechanism of how NO through S-nitrosylation of GRK6 and CK2α can enhance the phosphorylation of pSer129 α-syn in an animal model of PD.

Highlights

Parkinson’s disease (PD) is a common neurodegenerative disorder marked by impaired movement in association with a selective loss of dopaminergic neurons in the midbrain [1,2,3]
Samples were subjected to biotin-switch assay and we found that GRK6 was readily S-nitrosylated after treatment with GRK6 with S-nitrosoglutathione (GSNO), but GRK6 S-nitrosylation was not observed in the control (Fig 1A)
To determine if S-nitrosylation of casein kinase 2α (CK2α) and GRK6 is relevant to PD, we studied the level of S-nitrosylation of CK2α and GRK6 in a well-established A53T α-syn transgenic mouse model of PD [41]

Summary

Introduction

Parkinson’s disease (PD) is a common neurodegenerative disorder marked by impaired movement in association with a selective loss of dopaminergic neurons in the midbrain [1,2,3].

Methods

Results

Conclusion