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Quantitative analysis of microtubule dynamics during adhesion‐mediated growth cone guidance
Author(s) -
Lee Aih Cheun,
Suter Daniel M.
Publication year - 2008
Publication title -
developmental neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.716
H-Index - 129
eISSN - 1932-846X
pISSN - 1932-8451
DOI - 10.1002/dneu.20662
Subject(s) - microtubule , growth cone , microbiology and biotechnology , biology , actin , microtubule nucleation , biophysics , actin remodeling , actin cytoskeleton , cytoskeleton , microtubule polymerization , adhesion , actin remodeling of neurons , tubulin , chemistry , cell , biochemistry , axon , centrosome , organic chemistry , cell cycle
During adhesion‐mediated neuronal growth cone guidance microtubules undergo major rearrangements. However, it is unknown whether microtubules extend to adhesion sites because of changes in plus‐end polymerization and/or translocation dynamics, because of changes in actin–microtubule interactions, or because they follow the reorganization of the actin cytoskeleton. Here, we used fluorescent speckle microscopy to directly quantify microtubule and actin dynamics in Aplysia growth cones as they turn towards beads coated with the cell adhesion molecule apCAM. During the initial phase of adhesion formation, dynamic microtubules in the peripheral domain preferentially explore apCAM‐beads prior to changes in growth cone morphology and retrograde actin flow. Interestingly, these early microtubules have unchanged polymerization rates but spend less time in retrograde translocation due to uncoupling from actin flow. Furthermore, microtubules exploring the adhesion site spend less time in depolymerization. During the later phase of traction force generation, the central domain advances and more microtubules in the peripheral domain extend because of attenuation of actin flow and clearance of F‐actin structures. Microtubules in the transition zone and central domain, however, translocate towards the adhesion site in concert with actin arcs and bundles, respectively. We conclude that adhesion molecules guide neuronal growth cones and underlying microtubule rearrangements largely by differentially regulating microtubule–actin coupling and actin movements according to growth cone region and not by controlling plus‐end polymerization rates. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008