目的:与G蛋白偶联受体或受体酪氨酸激酶相反,通过尼古丁乙酰胆碱受体(nAChRs)激活ERK的潜在机制,配体门控离子通道家族的成员,仍未阐明。本研究旨在描述由α4β2nAChR亚型激活ERK的信号通路,这与尼古丁成瘾和各种精神障碍有关。
方法:采用功能丧失策略和具有独特功能特征的arrestin2/PKCβII突变体来鉴定参与ERK激活的细胞成分和过程。
结果:在细胞核内观察到通过α4β2nAChR激活的ERK,并需要arrestin2和PKCβII的核易位,表现出相互增强。α4β2nAChR刺激对PKCβII的激活通过增强arrestin2与importinβ1的相互作用来促进arrestin2的核易位。除了支架激活细胞核中的ERK,arrestin2与GRK2合作,促进了Src/Syk/PKCβII信号级联的激活,导致PKCβII以Gβγ依赖的方式进入核。在核本地化后,PKCβII通过Mdm2进行泛素化,并与MEK1相互作用,导致ERK激活。总之,α4β2nAChR介导的ERK在细胞核中的激活涉及arrestin2和PKCβII的核易位,这是通过正反馈增强相互促进的。
结论:由于α4β2nAChRs在包括药物成瘾和精神障碍在内的各种细胞过程中起关键作用,我们的发现将为了解α4β2nAChR相关疾病的发病机制提供见解,并可能促进靶向治疗干预措施的发展.
OBJECTIVE: In contrast to G protein-coupled receptors or receptor tyrosine kinases, the mechanism underlying ERK activation through nicotine acetylcholine receptors (nAChRs), members of the ligand-gated ion channel family, remains poorly elucidated. This study aimed to delineate the signaling pathway responsible for ERK activation by the α4β2 nAChR subtype, which is implicated in nicotine addiction and various mental disorders.
METHODS: Loss-of-function strategies and mutants of arrestin2/PKCβII with distinct functional characteristics were employed to identify the cellular components and processes involved in ERK activation.
RESULTS: ERK activation via α4β2 nAChR was observed within the nucleus and necessitated the nuclear translocation of arrestin2 and PKCβII, which exhibited mutual augmentation. Activation of PKCβII by α4β2 nAChR stimulation facilitated the nuclear translocation of arrestin2 by enhancing its interaction with importin β1. Apart from scaffolding ERK activation in the nucleus, arrestin2, in cooperation with GRK2, facilitated the activation of the Src/Syk/PKCβII signaling cascade, leading to the nuclear entry of PKCβII in a Gβγ-dependent manner. Upon nuclear localization, PKCβII underwent ubiquitination by Mdm2 and interacted with MEK1, resulting in ERK activation. In summary, α4β2 nAChR-mediated ERK activation in the nucleus involves the nuclear translocation of arrestin2 and PKCβII, which is reciprocally facilitated via positive feedback augmentation.
CONCLUSIONS: As α4β2 nAChRs play a pivotal role in various cellular processes including drug addiction and mental disorders, our findings will offer insights into understanding the pathogenesis of α4β2 nAChR-related disorders and may facilitate the development of targeted therapeutic interventions.