Myosin II Activity Facilitates Microtubule Bundling in the Neuronal Growth Cone Neck

• Published in: Developmental cell 2008-07, Vol.15 (1), p.163-169
• Main Authors: Burnette, Dylan T., Ji, Lin, Schaefer, Andrew W., Medeiros, Nelson A., Danuser, Gaudenz, Forscher, Paul
• Format: Article
• Language: English
• Subjects: Actins - metabolism; Actins - physiology; Animals; Aplysia - cytology; Biological and medical sciences; Cell Culture Techniques; Cell differentiation, maturation, development, hematopoiesis; Cell physiology; Cell structures and functions; CELLBIO; Cells, Cultured; Cytoskeleton, cytoplasm. Intracellular movements; Fundamental and applied biological sciences. Psychology; Growth Cones - physiology; Growth Cones - ultrastructure; Heterocyclic Compounds, 4 or More Rings - pharmacology; Immunohistochemistry; Kymography; Microtubules - metabolism; Microtubules - physiology; Microtubules - ultrastructure; Molecular and cellular biology; MOLNEURO; Myosin Type II - antagonists & inhibitors; Myosin Type II - physiology; Myosin Type II - ultrastructure; Neurons - physiology; Neurons - ultrastructure; Time Factors
• ISSN: 1534-5807; 1878-1551
• DOI: 10.1016/j.devcel.2008.05.016

The cell biological processes underlying axon growth and guidance are still not well understood. An outstanding question is how a new segment of the axon shaft is formed in the wake of neuronal growth cone advance. For this to occur, the highly dynamic, splayed-out microtubule (MT) arrays characteristic of the growth cone must be consolidated (bundled together) to form the core of the axon shaft. MT-associated proteins stabilize bundled MTs, but how individual MTs are brought together for initial bundling is unknown. Here, we show that laterally moving actin arcs, which are myosin II-driven contractile structures, interact with growing MTs and transport them from the sides of the growth cone into the central domain. Upon Myosin II inhibition, the movement of actin filaments and MTs immediately stopped and MTs unbundled. Thus, Myosin II-dependent compressive force is necessary for normal MT bundling in the growth cone neck.