Multimotor cargo navigation in microtubule networks with various mesh sizes

Area of Science:

• Cellular biology
• Biophysics
• Motor proteins

Background:

• Kinesin motor proteins drive intracellular transport via microtubules.
• Kinesin transport is influenced by external physical factors and motor interactions.

Purpose of the Study:

• To investigate how motor number and microtubule network density physically regulate kinesin-driven transport.
• To quantify the effects of these parameters on cargo navigation and movement dynamics.

Main Methods:

• In vitro reconstitution of kinesin-driven transport using quantum dot cargoes with varying numbers of kinesin motors (1-10).
• Utilizing increasingly dense microtubule networks to simulate complex cellular environments.
• Quantifying transport parameters such as distance, association time, speed, tortuosity, and persistence length.

Main Results:

• Increasing the number of kinesin motors significantly enhanced cargo transport: distance walked (2x), association time (4-5x), and average speed (2x).
• Multiple motors increased trajectory persistence length (5-8x), indicating more directed movement.
• Transport parameters showed a linear dependence on microtubule network mesh size for multi-motor cargoes.

Conclusions:

• Both the number of motors per cargo and the density of the microtubule network are critical physical regulators of kinesin-mediated transport.
• These findings provide insights into the physical control mechanisms governing intracellular cargo trafficking.