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Mammalian Kinesin-3 motors are dimeric in vivo and move by processive motility upon release of autoinhibition.

Authors: Hammond, Jennetta W  Cai, Dawen  Blasius, T Lynne  Li, Zhe  Jiang, Yuyang  Jih, Gloria T  Meyhofer, Edgar  Verhey, Kristen J 
Citation: Hammond JW, etal., PLoS Biol. 2009 Mar 31;7(3):e72. doi: 10.1371/journal.pbio.1000072.
Pubmed: (View Article at PubMed) PMID:19338388
DOI: Full-text: DOI:10.1371/journal.pbio.1000072

Kinesin-3 motors drive the transport of synaptic vesicles and other membrane-bound organelles in neuronal cells. In the absence of cargo, kinesin motors are kept inactive to prevent motility and ATP hydrolysis. Current models state that the Kinesin-3 motor KIF1A is monomeric in the inactive state and that activation results from concentration-driven dimerization on the cargo membrane. To test this model, we have examined the activity and dimerization state of KIF1A. Unexpectedly, we found that both native and expressed proteins are dimeric in the inactive state. Thus, KIF1A motors are not activated by cargo-induced dimerization. Rather, we show that KIF1A motors are autoinhibited by two distinct inhibitory mechanisms, suggesting a simple model for activation of dimeric KIF1A motors by cargo binding. Successive truncations result in monomeric and dimeric motors that can undergo one-dimensional diffusion along the microtubule lattice. However, only dimeric motors undergo ATP-dependent processive motility. Thus, KIF1A may be uniquely suited to use both diffuse and processive motility to drive long-distance transport in neuronal cells.


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CRRD Object Information
CRRD ID: 12914798
Created: 2017-07-13
Species: All species
Last Modified: 2017-07-13
Status: ACTIVE


RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.