A live-cell marker to visualize the dynamics of stable microtubules throughout the cell cycle

Area of Science:

• Cell Biology
• Cytoskeleton Dynamics
• Molecular Motors

Background:

• The microtubule (MT) cytoskeleton is crucial for intracellular transport and cell division.
• Different MT subsets with varying stability and function exist, but visualizing stable MTs in living cells has been challenging.
• Existing live-cell markers primarily focus on dynamic MTs, leaving stable MT dynamics poorly understood.

Purpose of the Study:

• To develop a novel live-cell marker for visualizing stable microtubules with high spatiotemporal resolution.
• To investigate the dynamics and behavior of stable MTs during cellular processes.
• To enable the exploration of how different MT subsets contribute to cellular organization and transport.

Main Methods:

• Development of StableMARK, a live-cell marker utilizing a rigor mutant of Kinesin-1.
• Selective binding of the Kinesin-1 rigor mutant to stable MTs without disrupting MT organization or organelle transport.
• Live-cell imaging to observe stable MTs before, during, and after cell division.

Main Results:

• StableMARK selectively labels stable MTs in living cells, allowing visualization with high spatiotemporal resolution.
• Stable MTs identified by StableMARK are long-lived, exhibit continuous remodeling, and resist depolymerization upon laser severing.
• The marker facilitated visualization of the spatiotemporal regulation of MT stability throughout the cell cycle.

Conclusions:

• StableMARK is an effective tool for visualizing stable microtubules in living cells.
• This marker overcomes previous limitations in studying stable MT dynamics.
• It opens new avenues for exploring the roles of distinct microtubule populations in cellular functions.