Related Experiment Video

Updated: Jun 18, 2025

Reconstitution of Basic Mitotic Spindles in Spherical Emulsion Droplets
10:52

Reconstitution of Basic Mitotic Spindles in Spherical Emulsion Droplets

Published on: August 13, 2016

9.8K

Eg5 UFMylation promotes spindle organization during mitosis

Guangxu Li1,2,3, Yuanjiang Huang1,2,3, Wenbo Han1,2,3

  • 1Furong Laboratory, Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.

Cell Death & Disease
|July 31, 2024
PubMed

Insights

Newly identified UFMylation of Eg5 motor protein is crucial for proper mitotic spindle organization and cell division. This ubiquitin-like modification ensures correct spindle assembly and progression through mitosis.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • UFMylation is a conserved ubiquitin-like modification essential for cellular processes.
  • Previous studies linked UFMylation to mitosis, but substrate identification was limited.
  • Mutations in UFMylation pathway components are associated with microcephaly.

Purpose of the Study:

  • To identify novel substrates of UFMylation involved in mitosis.
  • To elucidate the mechanism by which UFMylation regulates mitotic progression.
  • To investigate the role of Eg5 UFMylation in spindle assembly and cell division.

Main Methods:

  • Identification of Eg5 as a UFMylation substrate using biochemical assays.
  • Site-directed mutagenesis to identify the UFMylation site (Lys564).
  • Immunofluorescence microscopy to assess co-localization and localization of Eg5 and UFM1.
  • Analysis of mitotic progression and cell division in HeLa cells expressing wild-type and mutant Eg5.

Main Results:

  • Eg5 was identified as a novel UFMylation substrate, with Lys564 being the key site.
  • UFMylation of Eg5 affects its mono-ubiquitination but not its transcription, phosphorylation, or stability.
  • UFMylated Eg5 and UFM1 co-localize at the centrosome and spindle apparatus during mitosis.
  • Defective UFMylation impairs Eg5 spindle localization, leading to shorter spindles, metaphase arrest, and failed cell division.

Conclusions:

  • Eg5 UFMylation is essential for proper mitotic spindle organization and function.
  • This modification plays a critical role in regulating mitotic progression and cell proliferation.
  • Understanding Eg5 UFMylation provides insights into the mechanisms controlling cell division and potential therapeutic targets.

More Related Videos

Examination of Mitotic and Meiotic Fission Yeast Nuclear Dynamics by Fluorescence Live-cell Microscopy12:04

Examination of Mitotic and Meiotic Fission Yeast Nuclear Dynamics by Fluorescence Live-cell Microscopy

Published on: June 24, 2019

9.5K
Meiotic Spindle Assessment in Mouse Oocytes by siRNA-mediated Silencing09:16

Meiotic Spindle Assessment in Mouse Oocytes by siRNA-mediated Silencing

Published on: October 11, 2015

11.7K

Related Concept Videos

Spindle Assembly02:50

Spindle Assembly

Spindle assembly occurs through three, often coexisting, pathways – the centrosome-mediated pathway, the chromatin-mediated pathway, and the microtubule-mediated pathway – collectively contributing to form a robust spindle apparatus.
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a...
3.6K
The Mitotic Spindle02:27

The Mitotic Spindle

The mitotic spindle—or spindle apparatus—is a eukaryotic, cytoskeletal structure made up of long protein fibers called microtubules. Formed during cell division, the spindle separates sister chromatids and moves them to opposite ends of a parental cell, where the now individual chromosomes are distributed to two daughter cell nuclei.
The bipolar configuration of the mitotic spindle facilitates chromosomal segregation, preparing the cell for division. One mechanism that ensures...
6.5K
Forces Acting on Chromosomes02:11

Forces Acting on Chromosomes

During mitosis, chromosome movements occur through the interplay of multiple piconewton level forces. In prometaphase, these forces help in chromosome assembly or congression at the equatorial plane, eventually leading to their alignment at the metaphase plate. The forces acting on the chromosomes are space and time-dependent; therefore, they vary with the position of the chromosomes as the cell progresses through mitosis. 
Microtubules and motor proteins exert two types of forces on...
3.3K
Microtubule Instability02:17

Microtubule Instability

Microtubules are hollow cylindrical filaments having a diameter of approximately 25 nm and a length that varies from 200 nm to 25 μm. GTP-bound tubulin subunits form αβ-heterodimers for microtubule assembly. These core building blocks interact longitudinally, polymerizing into protofilaments. The protofilaments then interact with one another through lateral bonding forces to form stable cylindrical microtubules. These cylindrical filaments are dynamic as they undergo repeated...
5.0K
Disassembly of Intermediate Filaments01:35

Disassembly of Intermediate Filaments

Intermediate filaments (IFs) do not undergo spontaneous disassembly. Enzymes, kinases, and phosphatases add and remove phosphates from specific sites to regulate their disassembly. The IF concentration in the cytoplasm also regulates the disassembly. If the concentration crosses a threshold, it activates the protein kinases in the vicinity, allowing the phosphorylation of IFs.
Keratin proteins, found at the cell periphery near cell junctions, undergo a cycle of assembly and disassembly. In Type...
2.1K
Attachment of Sister Chromatids02:57

Attachment of Sister Chromatids

As cells progress into mitosis, the nuclear envelope breaks down, and the condensed chromosomes are exposed to the array of bipolar microtubules of the mitotic spindle. The kinetochore, a large, disc-shaped protein complex, is present at the centromere region of the sister chromatids and acts as a binding site for the microtubules.  Usually, the plus-end of a single microtubule is embedded within the kinetochore. However, some kinetochores first establish lateral contact with the side-wall...
3.2K