Multiple kinesins speed up cargo transport in crowded environments by sharing load

Area of Science:

• Cellular biology
• Biophysics
• Molecular motors

Background:

• Kinesin motors are essential for intracellular transport along microtubules.
• Determining the instantaneous number of motors actively engaged in cargo transport has been a significant challenge.
• The relationship between cargo velocity, motor number, and cytoplasmic crowding is not fully understood.

Purpose of the Study:

• To develop and apply a non-invasive method for quantifying instantaneous motor number.
• To investigate the impact of crowded cellular environments on multi-kinesin cargo transport.
• To elucidate the interplay between macromolecular crowding, kinesin tension, and cargo velocity.

Main Methods:

• Utilized a novel non-invasive technique to measure the instantaneous number of engaged kinesin motors.
• Conducted experiments in crowded cytoplasmic environments with varying crowder sizes.
• Employed stochastic kinesin simulations to validate findings on kinesin tension.

Main Results:

• Cargo velocity is dependent on the number of attached kinesin motors.
• The size of crowders in the cellular environment influences cargo motion.
• Kinesin tension was identified as a critical factor in collective motor-cargo transport.

Conclusions:

• The developed non-invasive method is broadly applicable for determining engaged motor numbers.
• Macromolecular crowding and kinesin tension significantly modulate kinesin-mediated cargo transport.
• This study provides new insights into the complex dynamics of intracellular transport.