Kinesin-4 KIF21B is a potent microtubule pausing factor.

Wilhelmina E van Riel, Ankit Rai, Sarah Bianchi, Eugene A Katrukha, Qingyang Liu, Albert Jr Heck, Casper C Hoogenraad, Michel O Steinmetz, Lukas C Kapitein, Anna Akhmanova

eLife 2017 Mar 14

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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.

Citation

Wilhelmina E van Riel, Ankit Rai, Sarah Bianchi, Eugene A Katrukha, Qingyang Liu, Albert Jr Heck, Casper C Hoogenraad, Michel O Steinmetz, Lukas C Kapitein, Anna Akhmanova. Kinesin-4 KIF21B is a potent microtubule pausing factor. eLife. 2017 Mar 14;6