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Sun H, Xu X, Luo J, Ma T, Cui J, Liu M, Xiong B, Zhu S, Liu JY. Mechanisms of PiT2-loop7 Missense Mutations Induced Pi Dyshomeostasis. Neurosci Bull 2023; 39:57-68. [PMID: 35713844 PMCID: PMC9849530 DOI: 10.1007/s12264-022-00893-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 04/14/2022] [Indexed: 01/25/2023] Open
Abstract
PiT2 is an inorganic phosphate (Pi) transporter whose mutations are linked to primary familial brain calcification (PFBC). PiT2 mainly consists of two ProDom (PD) domains and a large intracellular loop region (loop7). The PD domains are crucial for the Pi transport, but the role of PiT2-loop7 remains unclear. In PFBC patients, mutations in PiT2-loop7 are mainly nonsense or frameshift mutations that probably cause PFBC due to C-PD1131 deletion. To date, six missense mutations have been identified in PiT2-loop7; however, the mechanisms by which these mutations cause PFBC are poorly understood. Here, we found that the p.T390A and p.S434W mutations in PiT2-loop7 decreased the Pi transport activity and cell surface levels of PiT2. Furthermore, we showed that these two mutations attenuated its membrane localization by affecting adenosine monophosphate-activated protein kinase (AMPK)- or protein kinase B (AKT)-mediated PiT2 phosphorylation. In contrast, the p.S121C and p.S601W mutations in the PD domains did not affect PiT2 phosphorylation but rather impaired its substrate-binding abilities. These results suggested that missense mutations in PiT2-loop7 can cause Pi dyshomeostasis by affecting the phosphorylation-regulated cell-surface localization of PiT2. This study helps understand the pathogenesis of PFBC caused by PiT2-loop7 missense mutations and indicates that increasing the phosphorylation levels of PiT2-loop7 could be a promising strategy for developing PFBC therapies.
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Affiliation(s)
- Hao Sun
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | - Xuan Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Junyu Luo
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | - Tingbin Ma
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Jiaming Cui
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Mugen Liu
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | - Bo Xiong
- Department of Forensic Medicine, Tongji Medical College, HUST, Wuhan, 430030, China
| | - Shujia Zhu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.
| | - Jing-Yu Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.
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Wang X, Xiao Q, Zhu Y, Qi H, Qu D, Yao Y, Jia Y, Guo J, Cheng J, Ji Y, Li G, Tao J. Glycosylation of β1 subunit plays a pivotal role in the toxin sensitivity and activation of BK channels. J Venom Anim Toxins Incl Trop Dis 2021; 27:e20200182. [PMID: 34149831 PMCID: PMC8183112 DOI: 10.1590/1678-9199-jvatitd-2020-0182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background: The accessory β1 subunits, regulating the pharmacological and biophysical properties of BK channels, always undergo post-translational modifications, especially glycosylation. To date, it remains elusive whether the glycosylation contributes to the regulation of BK channels by β1 subunits. Methods: Herein, we combined the electrophysiological approach with molecular mutations and biochemical manipulation to investigate the function roles of N-glycosylation in β1 subunits. Results: The results show that deglycosylation of β1 subunits through double-site mutations (β1 N80A/N142A or β1 N80Q/N142Q) could significantly increase the inhibitory potency of iberiotoxin, a specific BK channel blocker. The deglycosylated channels also have a different sensitivity to martentoxin, another BK channel modulator with some remarkable effects as reported before. On the contrary to enhancing effects of martentoxin on glycosylated BK channels under the presence of cytoplasmic Ca2+, deglycosylated channels were not affected by the toxin. However, the deglycosylated channels were surprisingly inhibited by martentoxin under the absence of cytoplasmic Ca2+, while the glycosylated channels were not inhibited under this same condition. In addition, wild type BK (α+β1) channels treated with PNGase F also showed the same trend of pharmacological results to the mutants. Similar to this modulation of glycosylation on BK channel pharmacology, the deglycosylated forms of the channels were activated at a faster speed than the glycosylated ones. However, the V1/2 and slope were not changed by the glycosylation. Conclusion: The present study reveals that glycosylation is an indispensable determinant of the modulation of β1-subunit on BK channel pharmacology and its activation. The loss of glycosylation of β1 subunits could lead to the dysfunction of BK channel, resulting in a pathological state.
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Affiliation(s)
- Xiaoli Wang
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China
| | - Qian Xiao
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yudan Zhu
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Hong Qi
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China
| | - Dongxiao Qu
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yu Yao
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China
| | - Yuxiang Jia
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China
| | - Jingkan Guo
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China.,Xinhua Translational Institute for Cancer Pain, Shanghai, China
| | - Jiwei Cheng
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Putuo Clinical Medical School, Anhui Medical University, Shanghai, China
| | - Yonghua Ji
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China.,Xinhua Translational Institute for Cancer Pain, Shanghai, China
| | - Guoyi Li
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Putuo Clinical Medical School, Anhui Medical University, Shanghai, China
| | - Jie Tao
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Putuo Clinical Medical School, Anhui Medical University, Shanghai, China
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Laedermann CJ, Abriel H, Decosterd I. Post-translational modifications of voltage-gated sodium channels in chronic pain syndromes. Front Pharmacol 2015; 6:263. [PMID: 26594175 PMCID: PMC4633509 DOI: 10.3389/fphar.2015.00263] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 10/23/2015] [Indexed: 02/06/2023] Open
Abstract
In the peripheral sensory nervous system the neuronal expression of voltage-gated sodium channels (Navs) is very important for the transmission of nociceptive information since they give rise to the upstroke of the action potential (AP). Navs are composed of nine different isoforms with distinct biophysical properties. Studying the mutations associated with the increase or absence of pain sensitivity in humans, as well as other expression studies, have highlighted Nav1.7, Nav1.8, and Nav1.9 as being the most important contributors to the control of nociceptive neuronal electrogenesis. Modulating their expression and/or function can impact the shape of the AP and consequently modify nociceptive transmission, a process that is observed in persistent pain conditions. Post-translational modification (PTM) of Navs is a well-known process that modifies their expression and function. In chronic pain syndromes, the release of inflammatory molecules into the direct environment of dorsal root ganglia (DRG) sensory neurons leads to an abnormal activation of enzymes that induce Navs PTM. The addition of small molecules, i.e., peptides, phosphoryl groups, ubiquitin moieties and/or carbohydrates, can modify the function of Navs in two different ways: via direct physical interference with Nav gating, or via the control of Nav trafficking. Both mechanisms have a profound impact on neuronal excitability. In this review we will discuss the role of Protein Kinase A, B, and C, Mitogen Activated Protein Kinases and Ca++/Calmodulin-dependent Kinase II in peripheral chronic pain syndromes. We will also discuss more recent findings that the ubiquitination of Nav1.7 by Nedd4-2 and the effect of methylglyoxal on Nav1.8 are also implicated in the development of experimental neuropathic pain. We will address the potential roles of other PTMs in chronic pain and highlight the need for further investigation of PTMs of Navs in order to develop new pharmacological tools to alleviate pain.
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Affiliation(s)
- Cedric J. Laedermann
- F.M. Kirby Neurobiology Research Center, Boston Children’s Hospital, Harvard Medical School, BostonMA, USA
| | - Hugues Abriel
- Department of Clinical Research, University of BernBern, Switzerland
| | - Isabelle Decosterd
- Pain Center, Department of Anesthesiology, Lausanne University Hospital (CHUV) and University of LausanneLausanne, Switzerland
- Department of Fundamental Neurosciences, University of LausanneLausanne, Switzerland
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Mining the virgin land of neurotoxicology: a novel paradigm of neurotoxic peptides action on glycosylated voltage-gated sodium channels. J Toxicol 2012; 2012:843787. [PMID: 22829817 PMCID: PMC3399347 DOI: 10.1155/2012/843787] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 04/17/2012] [Accepted: 05/24/2012] [Indexed: 12/30/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) are important membrane protein carrying on the molecular basis for action potentials (AP) in neuronal firings. Even though the structure-function studies were the most pursued spots, the posttranslation modification processes, such as glycosylation, phosphorylation, and alternative splicing associating with channel functions captured less eyesights. The accumulative research suggested an interaction between the sialic acids chains and ion-permeable pores, giving rise to subtle but significant impacts on channel gating. Sodium channel-specific neurotoxic toxins, a family of long-chain polypeptides originated from venomous animals, are found to potentially share the binding sites adjacent to glycosylated region on VGSCs. Thus, an interaction between toxin and glycosylated VGSC might hopefully join the campaign to approach the role of glycosylation in modulating VGSCs-involved neuronal network activity. This paper will cover the state-of-the-art advances of researches on glycosylation-mediated VGSCs function and the possible underlying mechanisms of interactions between toxin and glycosylated VGSCs, which may therefore, fulfill the knowledge in identifying the pharmacological targets and therapeutic values of VGSCs.
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