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Updated: Jul 23, 2026
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Myosin-Specific Adaptations of In vitro Fluorescence Microscopy-Based Motility Assays
Published on: February 4, 2021
Myosin IIB is required for growth cone motility
P C Bridgman1, S Dave, C F Asnes
1Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA. bridgmap@pcg.wustl.edu
Summary
Myosin IIB is crucial for growth cone shape and force generation during axon outgrowth. While its absence slows outgrowth, other myosins compensate, indicating a collaborative role in neuronal development.
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- Growth cones guide axon advancement and navigation.
- Actomyosin-based force generation and cell adhesion are critical for growth cone function.
- The precise molecular mechanisms driving growth cone shape modulation and traction force remain incompletely understood.
Purpose of the Study:
- To investigate the role of myosin IIB in growth cone force generation and shape dynamics.
- To compare the function of growth cones from myosin IIB knockout mice with those from wild-type littermates.
Main Methods:
- Quantification of growth cone shape dynamics.
- Measurement of filopodial-mediated traction force in growth cones.
- Comparison between myosin IIB knockout and wild-type mouse neurons.
Main Results:
- Myosin IIB knockout growth cones exhibited reduced spreading and altered shape dynamics and actin organization.
- Filopodial-mediated traction force was significantly decreased in knockout growth cones.
- Despite reductions, knockout filopodia could occasionally generate forces comparable to wild-type, suggesting the involvement of other myosins.
Conclusions:
- Myosin IIB is essential for normal growth cone spreading, shape modulation, and traction force generation.
- Myosin IIB functions in conjunction with other myosins to mediate these processes.
- These activities are vital for axon outgrowth, which is impaired but not abolished in myosin IIB knockout neurons.
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