Zhong Guisheng, He Jiang, Zhou Ruobo, Lorenzo Damaris, Babcock Hazen P, Bennett Vann, Zhuang Xiaowei
Department of Chemistry and Chemical Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, United States.
Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, United States.
Elife. 2014 Dec 23;3:e04581. doi: 10.7554/eLife.04581.
Actin, spectrin, and associated molecules form a periodic sub-membrane lattice structure in axons. How this membrane skeleton is developed and why it preferentially forms in axons are unknown. Here, we studied the developmental mechanism of this lattice structure. We found that this structure emerged early during axon development and propagated from proximal regions to distal ends of axons. Components of the axon initial segment were recruited to the lattice late during development. Formation of the lattice was regulated by the local concentration of βII spectrin, which is higher in axons than in dendrites. Increasing the dendritic concentration of βII spectrin by overexpression or by knocking out ankyrin B induced the formation of the periodic structure in dendrites, demonstrating that the spectrin concentration is a key determinant in the preferential development of this structure in axons and that ankyrin B is critical for the polarized distribution of βII spectrin in neurites.
肌动蛋白、血影蛋白及相关分子在轴突中形成周期性的亚膜晶格结构。这种膜骨架是如何发育形成的，以及为何它优先在轴突中形成，目前尚不清楚。在此，我们研究了这种晶格结构的发育机制。我们发现，这种结构在轴突发育早期出现，并从轴突的近端区域向远端延伸。轴突起始段的成分在发育后期才被招募到晶格中。晶格的形成受βII血影蛋白局部浓度的调控，轴突中的βII血影蛋白浓度高于树突。通过过表达或敲除锚蛋白B来提高树突中βII血影蛋白的浓度，可诱导树突中形成周期性结构，这表明血影蛋白浓度是该结构在轴突中优先发育的关键决定因素，且锚蛋白B对βII血影蛋白在神经突中的极性分布至关重要。
