Nde1 promotes Lis1 binding to full-length autoinhibited human dynein 1

Area of Science:

• Cellular biology
• Molecular motor function
• Protein-protein interactions

Background:

• Cytoplasmic dynein 1 is the main motor for retrograde intracellular transport along microtubules.
• Dynein activation requires opening of its autoinhibited Phi conformation, mediated by Lis1 and Nde1/Ndel1 proteins.

Purpose of the Study:

• To elucidate the mechanism by which Nde1 facilitates Lis1-mediated activation of the dynein motor.
• To identify key intermediates in the dynein activation pathway.

Main Methods:

• Biochemical reconstitution
• Cryo-electron microscopy
• Mutagenesis studies
• Motility assays

Main Results:

• Nde1 enhances Lis1 binding to autoinhibited dynein, promoting Phi conformation opening.
• A novel intermediate, 'Phi^L-Lis1' complex, was identified, featuring Lis1 binding to two motor domains.
• The Phi^L-Lis1 interface is crucial for dynein activation, and this intermediate forms rapidly with Nde1 presence.

Conclusions:

• Nde1 acts as a crucial cofactor, promoting the formation of a Lis1-dynein intermediate essential for motor activation.
• The findings provide mechanistic insights into how Nde1 facilitates Lis1-mediated opening of the dynein Phi conformation.