Innovative Review Highlights the Role of Rapsyn in Neuromuscular Junction and Congenital Myasthenic Syndrome

Dr. Shunqi Wang

Researchers from Nanchang University in China have published a review article titled “The Role of Rapsyn in Neuromuscular Junction and Congenital Myasthenic Syndrome” in the Biomolecules and Biomedicine. This review article, led by first author Xufeng Liao and senior author Shunqi Wang, provides a comprehensive overview of the critical role of Rapsyn in neuromuscular junction (NMJ) and congenital myasthenic syndrome (CMS), focusing on its essential function in nicotinic acetylcholine receptor (nAChR) clustering.

The neuromuscular junction (NMJ) is a specialized synapse connecting the motor neuron and skeletal muscle fiber, allowing for the transmission of action potentials and subsequent muscle contraction. Congenital myasthenic syndrome (CMS) is a rare genetic disorder that affects the NMJ and leads to muscle weakness and fatigue. The disorder can occur at any age and symptoms can vary from mild to severe, often affecting the respiratory muscles.

CMS is caused by mutations in several genes involved in the formation and maintenance of NMJ. These include Rapsyn – an intracellular scaffolding protein that plays a critical role in the clustering and maintenance of nicotinic acetylcholine receptors, which are essential for muscle contractions. It was first isolated from the Torpedo electric organ and named Torpedo43K protein because of its molecular weight.

A key finding of the review is that Rapsyn is not only expressed in muscle cells but also in non-muscle cells, and is tightly associated with cytoplasmic membranes. This indicates that the protein’s function extends beyond skeletal muscle-derived cells and nAChR clustering, potentially affecting GABAA receptor or AchR.

In addition to its role in NMJ formation and maintenance, the authors discuss the implications of Rapsyn mutations for CMS patients. The researchers also discuss the possible function of Rapsyn in the central nervous system (CNS), as patients with CMS due to the Rapsyn mutation respond remarkably to anticholinesterase drugs such as pyridostigmine, and sometimes the addition of 3,4 DAP, ephedrine or albuterol leads to significant clinical improvement. The review also delves into the potential functions of Rapsyn in the peripheral nervous system (PNS). This opens up new avenues for future research on Rapsyn’s role in various neurological conditions, and as our understanding of Rapsyn’s role in the nervous system expands, it will undoubtedly contribute to the development of more effective treatments for a range of neuromuscular and neurological disorders.

For more information on this innovative review, visit the Biomolecules and Biomedicine website.

中国南昌大学的研究人员在《生物分子与生物医学》期刊上发表了一篇名为《Rapsyn在神经肌肉连接和先天性肌无力综合症中的作用》的综述文章。该综述文章由第一作者廖旭峰和通讯作者王顺奇带领,全面阐述了Rapsyn在神经肌肉连接和先天性肌无力综合症中的关键作用,重点介绍了其在尼古丁乙酰胆碱受体(nAChR)聚集中的重要功能。

神经肌肉连接是连接运动神经元和骨骼肌纤维的专门突触,允许动作电位传导和随后的肌肉收缩。先天性肌无力综合症是一种罕见的遗传性疾病,影响神经肌肉连接,导致肌肉无力和疲劳。该疾病可在任何年龄发生,症状可以从轻微到严重,通常影响呼吸肌肉。

先天性肌无力综合症是由多种参与神经肌肉连接形成和维护的基因突变引起的。其中包括Rapsyn – 一种细胞内支架蛋白,在尼古丁乙酰胆碱受体的聚集和维护中发挥关键作用,这些受体对于肌肉收缩至关重要。它最初是从电鳐电器官中分离出来的,并因其分子量而被命名为“Torpedo43K蛋白”。

该综述的一个关键发现是,Rapsyn不仅表达在肌肉细胞中,而且还表达在非肌肉细胞中,并与细胞质膜密切相关。这表明该蛋白的功能超越了骨骼肌来源的细胞和nAChR聚集,可能影响GABAA受体或AchR。

除了在神经肌肉连接的形成和维护中的作用,作者还讨论了Rapsyn突变对先天性肌无力综合症患者的影响。研究人员还讨论了Rapsyn在中枢神经系统中的可能功能,因为由于Rapsyn突变导致的先天性肌无力综合症患者对抗胆碱酯

Reference: Liao X, Wang Y, Lai X, Wang S. The role of Rapsyn in neuromuscular junction and congenital myasthenic syndrome. Biomol Biomed [Internet]. 2023Feb.20 [cited 2023Apr.29];. Available from: https://www.bjbms.org/ojs/index.php/bjbms/article/view/8641 
Editor: Ermina Vukalic

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