Dynactin enhances the processivity of kinesin-2

Area of Science:

• Cell Biology
• Molecular Motors
• Cytoskeletal Dynamics

Background:

• Kinesin-2 is a critical microtubule-based motor protein found in various cell types.
• While recombinant kinesin-2 shows processive movement, the motility of native kinesin-2 holoenzymes remains uncharacterized.
• Kinesin-2's interaction with dynactin, a known processivity factor for cytoplasmic dynein, suggests potential modulation of its motor properties.

Purpose of the Study:

• To investigate the in vitro motility of single native kinesin-2 molecules.
• To determine the impact of dynactin on the processivity of native kinesin-2 motors.

Main Methods:

• Analysis of single native kinesin-2 molecule motility in vitro.
• Assessment of dynactin's effect on kinesin-2 velocity and run length.

Main Results:

• Individual native kinesin-2 molecules exhibit processive movement.
• Dynactin does not alter the velocity of kinesin-2 motors.
• Dynactin significantly increases the run length of kinesin-2 movements.

Conclusions:

• Native kinesin-2 motors are inherently processive.
• Dynactin binding enhances kinesin-2 processivity by increasing run length, not velocity.
• The interaction between kinesin-2 and dynactin has significant functional implications for motor activity.