# Mechanism of cytokinesis in fission yeast

> **NIH NIH R01** · YALE UNIVERSITY · 2021 · $226,524

## Abstract

1. Project summary: The long-range goal of the project is to understand the mechanism of cytokinesis in
enough detail to make useful mathematical models of the process that can predict the results of future
experiments. Our experimental organism, the fission yeast Schizosaccharomyces pombe, has been highly
advantageous for this work. Over the past 25 years we have provided more quantitative information about
cytokinesis in this organism than any other. Nevertheless, essential details are still missing and will be
addressed by three lines of research.
Our first goal is to determine the molecular organization of the fission yeast contractile ring. We will use
quantitative super resolution fluorescence microscopy to make a complete, quantitative inventory of fission
yeast cytokinesis proteins and the structures that they form from interphase through the end of mitosis.
The second goal is to measure protein turnover in cytokinesis nodes and contractile rings. Our computer
simulations of contractile ring constriction revealed that turnover of actin filaments, formins and myosin-II is
required to produce tension. The most likely mechanism of exchange is association and dissociation of
individual protein molecules over time, but our super resolution fluorescence microscopy data indicate that
whole nodes may appear and disappear by a mysterious mechanism during cytokinesis. We will use a new
microscopy method to measure the exchange of node and contractile ring proteins with cytoplasmic pools with
sufficient spatial resolution to distinguish the exchange of single molecules and whole structures.
These projects are powered by innovative methods to count protein molecules and measure their turnover by
high speed FPALM super resolution microscopy.
Both of these projects will provide essential information to improve mathematical models contractile ring
assembly and constriction, which we will pursue with collaborators.
The third project is new. We aim to use cryo-EM to determine high resolution structures of actin filament
barbed ends associated with two different formins: Cdc12, the cytokinesis formin from fission yeast and mDia1
from mice, which has biochemical properties that differ from Cdc12.
Given the evolutionary conservation of many of the participating molecules, I believe that studies of fission
yeast will establish the basic molecular pathways controlling cytokinesis in other eukaryotes.
1

## Key facts

- **NIH application ID:** 10381917
- **Project number:** 3R01GM026132-43S1
- **Recipient organization:** YALE UNIVERSITY
- **Principal Investigator:** THOMAS D. POLLARD
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $226,524
- **Award type:** 3
- **Project period:** 1978-07-01 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10381917

## Citation

> US National Institutes of Health, RePORTER application 10381917, Mechanism of cytokinesis in fission yeast (3R01GM026132-43S1). Retrieved via AI Analytics 2026-06-02 from https://api.ai-analytics.org/grant/nih/10381917. Licensed CC0.

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