Related Experiment Video

Updated: May 7, 2026

Studying Proteolysis of Cyclin B at the Single Cell Level in Whole Cell Populations
10:54

Studying Proteolysis of Cyclin B at the Single Cell Level in Whole Cell Populations

Published on: September 17, 2012

Specific activation of cdc25 tyrosine phosphatases by B-type cyclins: evidence for multiple roles of mitotic cyclins

K Galaktionov1, D Beach

  • 1Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, New York 11724.

Cell
|December 20, 1991
PubMed

Insights

Two new human CDC25 genes, cdc25A and cdc25B, were identified. They activate tyrosine phosphatase and are regulated by B-type cyclins, crucial for cell cycle control.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • The CDC25 gene product is a key regulator of cell cycle progression.
  • Tyrosine phosphorylation plays a critical role in cell cycle control.

Purpose of the Study:

  • To identify and characterize novel human CDC25 genes.
  • To investigate the regulatory mechanisms of CDC25 tyrosine phosphatase activity.

Main Methods:

  • Gene isolation and functional rescue of fission yeast mutants.
  • Antibody microinjection into HeLa cells to study mitotic arrest.
  • In vitro assays to measure tyrosine phosphatase activity and protein interactions.

Main Results:

  • Two novel human CDC25 genes, cdc25A and cdc25B, were isolated and functionally characterized.
  • cdc25A and cdc25B exhibit tyrosine phosphatase activity, stimulated by B-type cyclins (B1, B2) but not other cyclin types.
  • Association between cdc25A, cyclin B1, and cdc2 was observed in HeLa cells.
  • A conserved motif for cyclin interaction was identified in tyrosine phosphatases but absent in cdc25.

Conclusions:

  • B-type cyclins are multifunctional, regulating both cdc2 kinase activity and cdc25 tyrosine phosphatase activation.
  • cdc25A and cdc25B are key components in the cell cycle control pathway, activated by B-type cyclins.
  • Intermolecular interaction with cyclin B likely provides an activating domain to cdc25 phosphatases.

More Related Videos

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

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay12:26

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Published on: May 3, 2018

Related Concept Videos

Positive Regulator Molecules01:45

Positive Regulator Molecules

To consistently produce healthy cells, the cell cycle—the process that generates daughter cells—must be precisely regulated.
Positive Regulator Molecules02:39

Positive Regulator Molecules

Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
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...
Mitogens and the Cell Cycle02:38

Mitogens and the Cell Cycle

Mitogens and their receptors play a crucial role in controlling the progression of the cell cycle. However, the loss of mitogenic control over cell division leads to tumor formation. Therefore, mitogens and mitogen receptors play an important role in cancer research. For instance, the epidermal growth factor (EGF) - a type of mitogen and its transmembrane receptor (EGFR), decides the fate of the cell's proliferation. When EGF binds to EGFR, a member of the ErbB family of tyrosine kinase...
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...
Mitogens and the Cell Cycle02:38

Mitogens and the Cell Cycle

Mitogens and their receptors play a crucial role in controlling the progression of the cell cycle. However, the loss of mitogenic control over cell division leads to tumor formation. Therefore, mitogens and mitogen receptors play an important role in cancer research. For instance, the epidermal growth factor (EGF) - a type of mitogen and its transmembrane receptor (EGFR), decides the fate of the cell's proliferation. When EGF binds to EGFR, a member of the ErbB family of tyrosine kinase...