Related Experiment Video

Updated: Jul 20, 2026

Two- and Three-Dimensional Live Cell Imaging of DNA Damage Response Proteins
10:24

Two- and Three-Dimensional Live Cell Imaging of DNA Damage Response Proteins

Published on: September 28, 2012

A family of diverse Cul4-Ddb1-interacting proteins includes Cdt2, which is required for S phase destruction of the

Jianping Jin1, Emily E Arias, Jing Chen

  • 1Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA.

Molecular Cell
|September 5, 2006
PubMed

Insights

Researchers identified 18 Cul4-Ddb1-associated factors (DCAFs), including Cdt2. Cdt2 is crucial for degrading the Cdt1 protein, ensuring proper DNA replication and cell cycle regulation.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Cul4 E3 ubiquitin ligases are crucial for cellular processes but have few identified substrate receptors.
  • Ddb1 adaptor protein is a key component of Cul4 E3 ligases.

Purpose of the Study:

  • To identify novel substrate receptors for Cul4 E3 ubiquitin ligases.
  • To elucidate the function of these receptors in cell cycle regulation and DNA replication.

Main Methods:

  • Protein interaction studies to identify Ddb1- and Cul4-associated factors (DCAFs).
  • Functional assays in Xenopus egg extracts and human cells to determine the role of identified DCAFs.
  • Ubiquitylation assays to investigate substrate degradation pathways.

Main Results:

  • Identified 18 DCAFs, 14 with WD40 repeats, interacting with Ddb1 via a conserved WDXR motif.
  • DCAF2/Cdt2 targets the replication licensing protein Cdt1 for degradation in S phase and after DNA damage.
  • Depletion of Cdt2 leads to DNA rereplication and checkpoint activation.

Conclusions:

  • Cul4-Ddb1 E3 ligases possess diverse substrate receptors.
  • Cdt2 is a conserved Cul4-Ddb1 E3 ligase component essential for Cdt1 degradation and cell cycle control of DNA replication.

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

Visualization of DNA Repair Proteins Interaction by Immunofluorescence07:55

Visualization of DNA Repair Proteins Interaction by Immunofluorescence

Published on: June 26, 2020

Related Concept Videos

S-Cdk Initiates DNA Replication02:38

S-Cdk Initiates DNA Replication

The cell cycle is a series of events leading to DNA duplication followed by the division of cell content to form two daughter cells. The cell cycle progresses in four stages—the cell increases in size (gap 1 or G1-phase), duplicates its DNA (synthesis or S-phase), prepares to divide (gap 2 or G2-phase), and divides (mitosis or M-phase).
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
S-Cdk Initiates DNA Replication02:38

S-Cdk Initiates DNA Replication

The cell cycle is a series of events leading to DNA duplication followed by the division of cell content to form two daughter cells. The cell cycle progresses in four stages—the cell increases in size (gap 1 or G1-phase), duplicates its DNA (synthesis or S-phase), prepares to divide (gap 2 or G2-phase), and divides (mitosis or M-phase).
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
DNA Damage can Stall the Cell Cycle02:36

DNA Damage can Stall the Cell Cycle

In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
DNA Damage Can Stall the Cell Cycle02:36

DNA Damage Can Stall the Cell Cycle

In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
Negative Regulator Molecules01:23

Negative Regulator Molecules

Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
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...