Self-repair promotes microtubule rescue

Area of Science:

• Cell Biology
• Biophysics
• Cytoskeleton Dynamics

Background:

• Microtubule dynamic instability involves phases of growth and depolymerization (catastrophes).
• Rescue events terminate depolymerization, restoring microtubule elongation, but their origin is unclear.
• Understanding rescue mechanisms is crucial for comprehending microtubule regulation.

Purpose of the Study:

• To elucidate the underlying mechanism of microtubule rescue events.
• To investigate the role of microtubule lattice self-repair in microtubule dynamics.
• To determine if physical constraints influence microtubule repair and growth.

Main Methods:

• Utilized tubulin photo-conversion in cellular systems.
• Observed tubulin dimer incorporation into existing microtubule structures.
• Analyzed microtubule assembly in regions of mechanical stress, bundling, and crossing.

Main Results:

• Demonstrated that free tubulin dimers incorporate into structurally damaged microtubule lattice sites.
• Identified these incorporation sites as key rescue sites, rejuvenating microtubule growth.
• Showed that self-repair preferentially occurs in microtubules experiencing mechanical constraints, such as crossings or bends.
• Established a link between microtubule self-repair and mechanosensitive growth.

Conclusions:

• Microtubule lattice self-repair is the primary mechanism responsible for rescue events.
• The incorporation of free tubulin dimers into damaged sites facilitates microtubule rejuvenation.
• Microtubule self-repair contributes to mechanosensitive growth, promoting assembly under physical stress.