The Tail of Kinesin-14a in Giardia Is a Dual Regulator of Motility.

The Tail of Kinesin-14a in Giardia Is a Dual Regulator of Motility. Curr Biol. 2020 Jul 29;: Authors: Tseng KF, Mickolajczyk KJ, Feng G, Feng Q, Kwok ES, Howe J, Barbar EJ, Dawson SC, Hancock WO, Qiu W Abstract Kinesin-14s are microtubule-based motor proteins that play important roles in mitotic spindle assembly [1]. Ncd-type kinesin-14s are a subset of kinesin-14 motors that exist as homodimers with an N-terminal microtubule-binding tail, a coiled-coil central stalk (central stalk), a neck, and two identical C-terminal motor domains. To date, no Ncd-type kinesin-14 has been found to naturally exhibit long-distance minus-end-directed processive motility on single microtubules as individual homodimers. Here, we show that GiKIN14a from Giardia intestinalis [2] is an unconventional Ncd-type kinesin-14 that uses its N-terminal microtubule-binding tail to achieve minus-end-directed processivity on single microtubules over micrometer distances as a homodimer. We further find that although truncation of the N-terminal tail greatly reduces GiKIN14a processivity, the resulting tailless construct GiKIN14a-Δtail is still a minimally processive motor and moves its center of mass via discrete 8-nm steps on the microtubule. In addition, full-length GiKIN14a has significantly higher stepping and ATP hydrolysis rates than does GiKIN14a-Δtail. Inserting a flexible polypeptide linker into the central stalk of full-length GiKIN14a nearly reduces its ...
Source: Current Biology - Category: Biology Authors: Tags: Curr Biol Source Type: research