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

Kuo Fu Tseng, Keith J. Mickolajczyk, Guangxi Feng, Qingzhou Feng, Ethiene S. Kwok, Jesse Howe, Elisar J. Barbar, Scott C. Dawson, William O. Hancock, Weihong Qiu

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


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 ATP hydrolysis rate to that of GiKIN14a-Δtail. Collectively, our results reveal that the N-terminal tail of GiKIN14a is a de facto dual regulator of motility and reinforce the notion of the central stalk as a key mechanical determinant of kinesin-14 motility [3].

Original languageEnglish (US)
Pages (from-to)3664-3671.e4
JournalCurrent Biology
Issue number18
StatePublished - Sep 21 2020

All Science Journal Classification (ASJC) codes

  • General Neuroscience
  • General Biochemistry, Genetics and Molecular Biology
  • General Agricultural and Biological Sciences


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