title: Actin, spectrin, and associated proteins form a periodic cytoskeletal structure in axons.
abstract: Actin and spectrin play important roles in neurons, but their organization in axons and dendrites remains unclear. We used stochastic optical reconstruction microscopy to study the organization of actin, spectrin, and associated proteins in neurons. Actin formed ringlike structures that wrapped around the circumference of axons and were evenly spaced along axonal shafts with a periodicity of ~180 to 190 nanometers. This periodic structure was not observed in dendrites, which instead contained long actin filaments running along dendritic shafts. Adducin, an actin-capping protein, colocalized with the actin rings. Spectrin exhibited periodic structures alternating with those of actin and adducin, and the distance between adjacent actin-adducin rings was comparable to the length of a spectrin tetramer. Sodium channels in axons were distributed in a periodic pattern coordinated with the underlying actin-spectrin-based cytoskeleton.
authors.affiliation: Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.forename: Guisheng
authors.initials: G
authors.lastname: Zhong
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Zhuang
mesh_terms: D051344:Actin Capping Proteins / Q000737:chemistry / Q000648:ultrastructure; D008841:Actin Cytoskeleton / Q000737:chemistry / Q000648:ultrastructure; D000199:Actins / Q000737:chemistry / Q000648:ultrastructure*; D000818:Animals; D001369:Axons / Q000737:chemistry* / Q000648:ultrastructure*; D002148:Calmodulin-Binding Proteins / Q000737:chemistry / Q000648:ultrastructure*; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000737:chemistry* / Q000648:ultrastructure*; D003712:Dendrites / Q000737:chemistry / Q000648:ultrastructure; D006624:Hippocampus / Q000648:ultrastructure; D007091:Image Processing, Computer-Assisted; D008856:Microscopy, Fluorescence / Q000379:methods; D009474:Neurons / Q000737:chemistry / Q000648:ultrastructure; D055503:Protein Multimerization; D051381:Rats; D017208:Rats, Wistar; D015222:Sodium Channels / Q000737:chemistry / Q000648:ultrastructure; D013049:Spectrin / Q000737:chemistry / Q000648:ultrastructure*; D000099291:Adducins
chemical_list: D051344:Actin Capping Proteins; D000199:Actins; D002148:Calmodulin-Binding Proteins; D015222:Sodium Channels; D013049:Spectrin; D000099291:Adducins