Castets Perrine, Ham Daniel J, Rüegg Markus A
Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
Biozentrum, University of Basel, Basel, Switzerland.
Front Mol Neurosci. 2020 Aug 28;13:162. doi: 10.3389/fnmol.2020.00162. eCollection 2020.
The neuromuscular junction (NMJ) is the chemical synapse connecting motor neurons and skeletal muscle fibers. NMJs allow all voluntary movements, and ensure vital functions like breathing. Changes in the structure and function of NMJs are hallmarks of numerous pathological conditions that affect muscle function including sarcopenia, the age-related loss of muscle mass and function. However, the molecular mechanisms leading to the morphological and functional perturbations in the pre- and post-synaptic compartments of the NMJ remain poorly understood. Here, we discuss the role of the metabolic pathway associated to the kinase TOR () in the development, maintenance and alterations of the NMJ. This is of particular interest as the TOR pathway has been implicated in aging, but its role at the NMJ is still ill-defined. We highlight the respective functions of the two TOR-associated complexes, TORC1 and TORC2, and discuss the role of localized protein synthesis and autophagy regulation in motor neuron terminals and sub-synaptic regions of muscle fibers and their possible effects on NMJ maintenance.
神经肌肉接头(NMJ)是连接运动神经元和骨骼肌纤维的化学突触。神经肌肉接头使所有自主运动成为可能,并确保呼吸等重要功能。神经肌肉接头的结构和功能变化是众多影响肌肉功能的病理状况的标志,包括肌肉减少症,即与年龄相关的肌肉质量和功能丧失。然而,导致神经肌肉接头突触前和突触后区室形态和功能紊乱的分子机制仍知之甚少。在这里,我们讨论与激酶TOR()相关的代谢途径在神经肌肉接头的发育、维持和改变中的作用。这一点特别值得关注,因为TOR途径与衰老有关,但其在神经肌肉接头处的作用仍不明确。我们强调了两种与TOR相关的复合物TORC1和TORC2各自的功能,并讨论了局部蛋白质合成和自噬调节在运动神经元终末以及肌肉纤维突触下区域中的作用,以及它们对神经肌肉接头维持可能产生的影响。