Developmental mechanism of the periodic membrane skeleton in axons
Guisheng Zhong,
Jiang He,
Ruobo Zhou,
Damaris Lorenzo,
Hazen P Babcock,
Vann Bennett,
Xiaowei Zhuang
Affiliations
Guisheng Zhong
Department of Chemistry and Chemical Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, United States
Jiang He
Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, United States
Ruobo Zhou
Department of Chemistry and Chemical Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, United States
Damaris Lorenzo
Department of Biochemistry, Duke University, Durham, United States; Department of Neurobiology, Duke University, Durham, United States
Hazen P Babcock
Center for Brain Sciences, Harvard University, Cambridge, United States
Vann Bennett
Department of Neurobiology, Duke University, Durham, United States; Department of Biochemistry, Howard Hughes Medical Institute, Duke University, Durham, United States
Xiaowei Zhuang
Department of Chemistry and Chemical Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, United States; Department of Physics, Harvard University, Cambridge, United States
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.
