1. Site-directed MT1-MMP trafficking and surface insertion regulate AChR clustering and remodeling at developing NMJs
- Author
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Zora Chui-Kuen Chan, Hiu-Lam Rachel Kwan, Yin Shun Wong, Zhixin Jiang, Zhongjun Zhou, Kin Wai Tam, Ying-Shing Chan, Chi Bun Chan, and Chi Wai Lee
- Subjects
neuromuscular junction ,acetylcholine receptor ,extracellular matrix protein ,podosome ,membrane-type 1 matrix metalloproteinase ,Medicine ,Science ,Biology (General) ,QH301-705.5 - Abstract
At vertebrate neuromuscular junctions (NMJs), the synaptic basal lamina contains different extracellular matrix (ECM) proteins and synaptogenic factors that induce and maintain synaptic specializations. Here, we report that podosome-like structures (PLSs) induced by ubiquitous ECM proteins regulate the formation and remodeling of acetylcholine receptor (AChR) clusters via focal ECM degradation. Mechanistically, ECM degradation is mediated by PLS-directed trafficking and surface insertion of membrane-type 1 matrix metalloproteinase (MT1-MMP) to AChR clusters through microtubule-capturing mechanisms. Upon synaptic induction, MT1-MMP plays a crucial role in the recruitment of aneural AChR clusters for the assembly of postsynaptic specializations. Lastly, the structural defects of NMJs in embryonic MT1-MMP-/- mice further demonstrate the physiological role of MT1-MMP in normal NMJ development. Collectively, this study suggests that postsynaptic MT1-MMP serves as a molecular switch to synaptogenesis by modulating local ECM environment for the deposition of synaptogenic signals that regulate postsynaptic differentiation at developing NMJs.
- Published
- 2020
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