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Kinesin-4 KIF21B is a potent microtubule pausing factor

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ABSTRACT

Microtubules are dynamic polymers that in cells can grow, shrink or pause, but the factors that promote pausing are poorly understood. Here, we show that the mammalian kinesin-4 KIF21B is a processive motor that can accumulate at microtubule plus ends and induce pausing. A few KIF21B molecules are sufficient to induce strong growth inhibition of a microtubule plus end in vitro. This property depends on non-motor microtubule-binding domains located in the stalk region and the C-terminal WD40 domain. The WD40-containing KIF21B tail displays preference for a GTP-type over a GDP-type microtubule lattice and contributes to the interaction of KIF21B with microtubule plus ends. KIF21B also contains a motor-inhibiting domain that does not fully block the interaction of the protein with microtubules, but rather enhances its pause-inducing activity by preventing KIF21B detachment from microtubule tips. Thus, KIF21B combines microtubule-binding and regulatory activities that together constitute an autonomous microtubule pausing factor.

Doi:: http://dx.doi.org/10.7554/eLife.24746.001

No MeSH data available.


DOI:http://dx.doi.org/10.7554/eLife.24746.042
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fig9: DOI:http://dx.doi.org/10.7554/eLife.24746.042

Mentions: In our recent paper (Doodhi et al., 2014), we have already performed a similar comparison of “kinesin-on-top-of-microtubule” to the intensity of single GFP molecules absorbed on glass, see Supplementary Figure S2B in that paper and Author response image 2. At that time, we compared the intensity of KIF5B-560-SxIP-GFP molecules running on the lattice of microtubules to the single GFP intensity of the same molecules attached to the coverslip at the moment just before complete bleaching. Author response image 2 shows the two distributions of fluorescent intensities (values of intensities at the microtubule tips are removed from original Figure S2B of Doodhi et al. 2014).10.7554/eLife.24746.042Author response image 2.


Kinesin-4 KIF21B is a potent microtubule pausing factor
DOI:http://dx.doi.org/10.7554/eLife.24746.042
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC5383399&req=5

fig9: DOI:http://dx.doi.org/10.7554/eLife.24746.042
Mentions: In our recent paper (Doodhi et al., 2014), we have already performed a similar comparison of “kinesin-on-top-of-microtubule” to the intensity of single GFP molecules absorbed on glass, see Supplementary Figure S2B in that paper and Author response image 2. At that time, we compared the intensity of KIF5B-560-SxIP-GFP molecules running on the lattice of microtubules to the single GFP intensity of the same molecules attached to the coverslip at the moment just before complete bleaching. Author response image 2 shows the two distributions of fluorescent intensities (values of intensities at the microtubule tips are removed from original Figure S2B of Doodhi et al. 2014).10.7554/eLife.24746.042Author response image 2.

View Article: PubMed Central - PubMed

ABSTRACT

Microtubules are dynamic polymers that in cells can grow, shrink or pause, but the factors that promote pausing are poorly understood. Here, we show that the mammalian kinesin-4 KIF21B is a processive motor that can accumulate at microtubule plus ends and induce pausing. A few KIF21B molecules are sufficient to induce strong growth inhibition of a microtubule plus end in vitro. This property depends on non-motor microtubule-binding domains located in the stalk region and the C-terminal WD40 domain. The WD40-containing KIF21B tail displays preference for a GTP-type over a GDP-type microtubule lattice and contributes to the interaction of KIF21B with microtubule plus ends. KIF21B also contains a motor-inhibiting domain that does not fully block the interaction of the protein with microtubules, but rather enhances its pause-inducing activity by preventing KIF21B detachment from microtubule tips. Thus, KIF21B combines microtubule-binding and regulatory activities that together constitute an autonomous microtubule pausing factor.

Doi:: http://dx.doi.org/10.7554/eLife.24746.001

No MeSH data available.