A change point analysis protocol for comparing intracellular transport by different molecular motor combinations

Area of Science:

• Cell Biology
• Biophysics
• Molecular Motors

Background:

• Intracellular transport relies on molecular motors moving along microtubules.
• Quantifying individual cargo behaviors and motor influences remains challenging.

Purpose of the Study:

• To develop and validate a novel protocol for analyzing cargo trajectory change points.
• To investigate how different motor families (Kinesin-1, Dynein-Dynactin-BicD2) affect transport dynamics.

Main Methods:

• Automated identification of velocity change points in cargo trajectories.
• Estimation of velocities and extrapolation to motor-specific distributions.
• Application to simulated data and experimental datasets (Kinesin-1, DDB, Kinesin-1/DDB).

Main Results:

• The new protocol demonstrates favorable comparison with existing methods using simulated data.
• Analysis of Kinesin-1, DDB, and combined motor transport revealed specific behaviors.
• Pausing behaviors consistent with tug-of-war models were observed.

Conclusions:

• The developed protocol accurately quantifies motor-driven intracellular transport dynamics.
• Simultaneous action of antagonistic motors can result in extended processive runs, enhancing overall transport.
• Findings provide insights into the complex regulation of intracellular cargo movement.