title: Molecular basis of reactive oxygen species-induced inactivation of α4β2 nicotinic acetylcholine receptors.
abstract: The α4β2 neuronal nicotinic acetylcholine receptors (nAChRs) are the most widespread heteromeric nAChR subtype in the brain, mediating fast synaptic transmission. Previous studies showed that α4β2 nAChRs could be inactivated by reactive oxygen species (ROS), but the underlying mechanism is still obscure. We found that H2O2 induced the rundown of ACh-evoked currents in human α4β2 nAChRs and the replacement of the conserved cysteine in the M1-M2 linker of either α4 Cys245 or β2 Cys237 with an alanine residue could prevent the current rundown. Structurally, α4 Cys245 and β2 Cys237 are hypothesized to be in close proximity when the receptor is activated. Western blotting results showed that α4 and β2 subunits were cross-linked when the agonist-bound receptor encountered H2O2, which could be prevented by the substitution of the conserved cysteine in the M1-M2 linker to an alanine. Thus, when agonist bound to the receptor, α4 Cys245 and β2 Cys237 came close to each other and ROS oxidized these conserved cysteines, leading subunits to be cross-linked and trapping α4β2 nAChRs into the inactivation state. In addition, we mimicked an experimental Parkinson's disease (PD) model in PC12 cells and found that ROS, generated by 6-hydroxydopamine (6-OHDA), could cause the current rundown in α4β2 nAChRs, which may play a role in PD.
authors.affiliation: Department of Neurobiology, Beijing Institute of Brain Disorders, Capital Medical University, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Center of Neural Regeneration and Repair, Beijing Key Laboratory of Brain Major Disorders-State Key Lab Incubation Base, Beijing Neuroscience Disciplines, Beijing 100069, China.
authors.forename: Junjun
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Neurobiology, Beijing Institute of Brain Disorders, Capital Medical University, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Center of Neural Regeneration and Repair, Beijing Key Laboratory of Brain Major Disorders-State Key Lab Incubation Base, Beijing Neuroscience Disciplines, Beijing 100069, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Medical Experiment and Test Center, Capital Medical University, Beijing 100069, China.
authors.forename: Fenqin
authors.initials: F
authors.lastname: Xue
authors.affiliation: Division of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013, USA.
authors.forename: Yongchang
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Department of Neurobiology, Beijing Institute of Brain Disorders, Capital Medical University, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Center of Neural Regeneration and Repair, Beijing Key Laboratory of Brain Major Disorders-State Key Lab Incubation Base, Beijing Neuroscience Disciplines, Beijing 100069, China. Electronic address: huiyang@ccmu.edu.cn.
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Neurobiology, Beijing Institute of Brain Disorders, Capital Medical University, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Center of Neural Regeneration and Repair, Beijing Key Laboratory of Brain Major Disorders-State Key Lab Incubation Base, Beijing Neuroscience Disciplines, Beijing 100069, China. Electronic address: jlzhang@ccmu.edu.cn.
authors.forename: Jianliang
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000595:Amino Acid Sequence; D057809:HEK293 Cells; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D008958:Models, Molecular; D018722:Nicotinic Agonists / Q000494:pharmacology; D011485:Protein Binding; D000072756:Protein Conformation, alpha-Helical; D054730:Protein Interaction Domains and Motifs; D020836:Protein Structure, Quaternary; D017382:Reactive Oxygen Species / Q000378:metabolism*; D011978:Receptors, Nicotinic / Q000737:chemistry / Q000378:metabolism*
chemical_list: D018722:Nicotinic Agonists; D017382:Reactive Oxygen Species; D011978:Receptors, Nicotinic; C403531:nicotinic receptor alpha4beta2; D000109:Acetylcholine
keywords: Neuronal nicotinic acetylcholine receptors; Parkinson's disease; Reactive oxygen species