Related Experiment Video

Updated: Jul 5, 2026

Real-Time Monitoring of Aurora kinase A Activation using Conformational FRET Biosensors in Live Cells
06:29

Real-Time Monitoring of Aurora kinase A Activation using Conformational FRET Biosensors in Live Cells

Published on: July 30, 2020

Aurora A phosphorylates MCAK to control ran-dependent spindle bipolarity

Xin Zhang1, Stephanie C Ems-McClung, Claire E Walczak

  • 1Departments of Biochemistry and Molecular Biology, and Medical Sciences, Indiana University, Bloomington, IN 47405, USA.

Molecular Biology of the Cell
|April 25, 2008
PubMed

Insights

Mitotic centromere-associated kinesin (MCAK) regulation by Aurora A is crucial for spindle formation. Aurora A controls MCAK

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Mitotic centromere-associated kinesin (MCAK) plays roles in mitosis.
  • MCAK localization and activity at chromatin/kinetochores are regulated by Aurora B kinase.
  • Regulation of cytoplasmic and spindle pole-localized MCAK is not well understood.

Purpose of the Study:

  • To investigate the regulation of MCAK by Aurora A kinase.
  • To understand MCAK's role in microtubule organization and spindle formation in the absence of chromatin and centrosomes.

Main Methods:

  • Utilized Xenopus egg extracts to assemble spindles without chromatin or centrosomes.
  • Investigated MCAK localization and activity using immunofluorescence and biochemical assays.
  • Analyzed the role of specific Aurora A phosphorylation sites (S196 and S719) on MCAK function.

Main Results:

  • MCAK localization and activity are regulated by Aurora A in Xenopus egg extracts.
  • Aurora A-dependent phosphorylation of MCAK at S196 regulates pole focusing at aster centers.
  • Phosphorylation at S719 by Aurora A enhances bipolar spindle formation.
  • MCAK colocalizes with NuMA and XMAP215 at the center of Ran asters.

Conclusions:

  • Aurora A plays a key role in regulating MCAK localization and activity during spindle assembly.
  • MCAK phosphorylation by Aurora A at S196 and S719 contributes to proper pole focusing and bipolar spindle formation.
  • This study identifies novel roles for MCAK at spindle poles and highlights Aurora A as a key regulator of spindle bipolarity.

More Related Videos

Live Cell Imaging to Assess the Dynamics of Metaphase Timing and Cell Fate Following Mitotic Spindle Perturbations07:14

Live Cell Imaging to Assess the Dynamics of Metaphase Timing and Cell Fate Following Mitotic Spindle Perturbations

Published on: September 20, 2019

Combining Mitotic Cell Synchronization and High Resolution Confocal Microscopy to Study the Role of Multifunctional Cell Cycle Proteins During Mitosis08:33

Combining Mitotic Cell Synchronization and High Resolution Confocal Microscopy to Study the Role of Multifunctional Cell Cycle Proteins During Mitosis

Published on: December 5, 2017

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 microtubule array...
M-Cdk Drives Transition Into Mitosis02:15

M-Cdk Drives Transition Into Mitosis

Checkpoints throughout the cell cycle serve as safeguards and gatekeepers, allowing the cell cycle to progress in favorable conditions and slow or halt it in problematic ones. This regulation is known as the cell cycle control system.
Cyclin-dependent kinases, or Cdks, work in concert with cyclins to control cell cycle transitions. M-Cdk, a complex of Cdk1 bound to M cyclin, is a well-known example of this coordinated control that drives the transition from the G2 to the M phase.
M cyclin...
The Spindle Assembly Checkpoint02:19

The Spindle Assembly Checkpoint

The spindle assembly checkpoint is a molecular surveillance mechanism ensuring the fidelity of chromosome segregation during anaphase. The checkpoint monitors the completion of all the prerequisite steps before chromosome segregation to determine whether the segregation process should proceed or be delayed.
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
Anaphase Promoting Complex00:50

Anaphase Promoting Complex

The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...
Anaphase Promoting Complex00:50

Anaphase Promoting Complex

The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...
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 of a...