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Updated: May 11, 2026
Neuronal Cell Cultures from Aplysia for High-Resolution Imaging of Growth Cones
Published on: February 20, 2008
Different modes of growth cone collapse in NG 108-15 cells
Philipp Rauch1, Paul Heine, Barbara Goettgens
1Institute of Experimental Physics I, University of Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany.
Abstract:
In the fundamental process of neuronal path-finding, a growth cone at the tip of every neurite detects and follows multiple guidance cues regulating outgrowth and initiating directional changes. While the main focus of research lies on the cytoskeletal dynamics underlying growth cone advancement, we investigated collapse and retraction mechanisms in NG108-15 growth cones transiently transfected with mCherry-LifeAct and pCS2+/EMTB-3XGFP for filamentous actin and microtubules, respectively. Using fluorescence time lapse microscopy we could identify two distinct modes of growth cone collapse leading either to neurite retraction or to a controlled halt of neurite extension. In the latter case, lateral movement and folding of actin bundles (filopodia) confine microtubule extension and limit microtubule-based expansion processes without the necessity of a constantly engaged actin turnover machinery. We term this previously unreported second type fold collapse and suggest that it marks an intermediate-term mode of growth regulation closing the gap between full retraction and small scale fluctuations.
Insights
Researchers identified two distinct growth cone collapse modes in NG108-15 cells. One mode causes neurite retraction, while a novel "fold collapse" halts extension by folding actin structures, regulating neuronal growth.
Area of Science:
- Neuroscience
- Cell Biology
- Developmental Biology
Background:
- Neuronal path-finding relies on growth cones responding to guidance cues.
- Cytoskeletal dynamics are crucial for growth cone advancement.
- Mechanisms of growth cone collapse and retraction are less understood.
Purpose of the Study:
- To investigate distinct modes of growth cone collapse and retraction.
- To characterize the role of actin and microtubules in these processes.
- To identify novel mechanisms of growth cone regulation.
Main Methods:
- Utilized NG108-15 cells transiently transfected with fluorescent markers for actin (mCherry-LifeAct) and microtubules (pCS2+/EMTB-3XGFP).
- Employed fluorescence time-lapse microscopy to observe growth cone dynamics.
- Analyzed cytoskeletal rearrangements during collapse and retraction events.
Main Results:
- Identified two distinct modes of growth cone collapse.
- One mode resulted in complete neurite retraction.
- A novel 'fold collapse' mode was observed, halting neurite extension via actin filopodia folding, confining microtubule extension without continuous actin turnover.
Conclusions:
- Growth cone collapse can lead to either neurite retraction or a regulated halt in extension.
- The newly described 'fold collapse' represents an intermediate-term growth regulation mechanism.
- This mechanism utilizes actin dynamics to control microtubule-based expansion, bridging full retraction and minor fluctuations.
