The AAA3 domain of cytoplasmic dynein acts as a switch to facilitate microtubule release
Related Experiment Video
Updated: Apr 19, 2026

Reconstitution of Basic Mitotic Spindles in Spherical Emulsion Droplets
Published on: August 13, 2016
Mark A DeWitt1, Caroline A Cypranowska2, Frank B Cleary1
1Biophysics Graduate Group, University of California, Berkeley, Berkeley, California, USA.
Abstract:
Cytoplasmic dynein is an AAA+ motor responsible for intracellular cargo transport and force generation along microtubules (MTs). Unlike kinesin and myosin, dynein contains multiple ATPase subunits, with AAA1 serving as the primary catalytic site. ATPase activity at AAA3 is also essential for robust motility, but its role in dynein's mechanochemical cycle remains unclear. Here, we introduced transient pauses in Saccharomyces cerevisiae dynein motility by using a slowly hydrolyzing ATP analog. Analysis of pausing behavior revealed that AAA3 hydrolyzes nucleotide an order of magnitude more slowly than AAA1, and the two sites do not coordinate. ATPase mutations to AAA3 abolish the ability of dynein to modulate MT release. Nucleotide hydrolysis at AAA3 lifts this 'MT gate' to allow fast motility. These results suggest that AAA3 acts as a switch that repurposes cytoplasmic dynein for fast cargo transport and MT-anchoring tasks in cells.
Related Concept Videos
Microtubule Associated Motor Proteins
The Movement of Organelles and Vesicles
Mechanism of Ciliary Motion
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
Anaphase A and B
Plus-end depolymerization releases tubulin heterodimers from the terminal region of the microtubule. As tubulin subunits are lost, the Ndc80 complexes detach...
Destabilization of Microtubules
Microtubules in Cell Motility

