# Mechanistic Analysis of Kinesin-14 Motility and Regulation for Bipolar Spindle Assembly

> **NIH NIH R01** · OREGON STATE UNIVERSITY · 2022 · $315,303

## Abstract

Project Summary: During mitotic cell division (mitosis), replicated chromosomes must be accurately segregated
into two daughter cells to ensure normal development and growth in all eukaryotes. Errors in chromosome
segregation can lead to aneuploidy, a hallmark of cancer and a host of associated health problems. As a result,
a major frontier in biomedical research is to understand the mechanisms that govern the assembly and
maintenance of the mitotic spindle, a microtubule-based bipolar machine responsible for accurate chromosome
segregation during mitosis. It is well established that proper assembly and maintenance of a bipolar mitotic
spindle requires the coordinated action of many microtubule-based kinesin motors (mitotic kinesins). However,
the mechanisms of individual mitotic kinesins and their regulation by partner proteins and coordination during
spindle assembly and maintenance remain poorly understood. The long-term goal of the PI is to reconstitute
bipolar mitotic spindles in vitro from purified proteins and to fully dissect the mechanisms, regulation and
coordination of mitotic kinesins in spindle assembly and maintenance. The focus of this project is on mitotic
kinesin-14s, which are known to form an antagonistic pair with kinesin-5s to drive bipolar spindle assembly. The
PI has established several foundational findings for this project, including that (1) the mitotic kinesin-14 KlpA
from Aspergillus nidulans (and its ortholog in Aspergillus niger) exhibits processive plus-end-directed motility on
single microtubules, and (2) the same KlpA in complex with two well-conserved partner proteins switches to
processive minus-end-directed motility on single microtubules. The latter discovery represents a first set of in
vitro studies showing that a mitotic kinesin-14 depends on partner proteins to gain processive minus-end-directed
motility. Building on these findings, this project is aimed at filling two major open questions that are key to
understanding how kinesin-14 opposes kinesin-5 in bipolar spindle assembly: (1) What is the molecular basis
underlying processive plus-end-directed kinesin-14 motility on single microtubules? (2) How are kinesin-14s
regulated by partner proteins to drive bipolar spindle assembly? This project uses an innovative combination of
multiple techniques, including single-molecule total internal reflection fluorescence microscopy, dark field
nanoparticle tracking, two-color high-precision fluorescence tracking, genetic incorporation of unnatural amino
acids, and high-resolution optical trapping. Results from this project will not only markedly broaden current
understanding of kinesin motility mechanisms but also provide a mechanistic understanding of kinesin-14
regulation in bipolar spindle assembly. Furthermore, this work will be a stepping stone toward the long-term goal
of a complete understanding of the mechanisms, regulation and coordination of kinesins in mitotic spindle
assembly and maintenance, and also pr...

## Key facts

- **NIH application ID:** 10442547
- **Project number:** 5R01GM127922-04
- **Recipient organization:** OREGON STATE UNIVERSITY
- **Principal Investigator:** Weihong Qiu
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $315,303
- **Award type:** 5
- **Project period:** 2019-09-01 → 2024-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10442547

## Citation

> US National Institutes of Health, RePORTER application 10442547, Mechanistic Analysis of Kinesin-14 Motility and Regulation for Bipolar Spindle Assembly (5R01GM127922-04). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10442547. Licensed CC0.

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