Related Experiment Video

Updated: Nov 16, 2025

Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
10:53

Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents

Published on: July 3, 2013

20.8K

ATR activation is regulated by dimerization of ATR activating proteins

Vaughn Thada1, David Cortez1

  • 1Department of Biochemistry, Vanderbilt University School of Medicine, Nashville Tennessee, USA.

The Journal of Biological Chemistry
|February 26, 2021
PubMed

Insights

Dimerization of TOPBP1 and ETAA1 enhances ATR kinase activation, crucial for DNA repair and genome stability. This finding clarifies the mechanism of ATR signaling and its role in cellular stress responses.

Area of Science:

  • Cellular Biology
  • Molecular Biology
  • Genetics

Background:

  • The checkpoint kinase ATR is vital for DNA repair and replication stress responses.
  • TOPBP1 and ETAA1 are known activators of ATR signaling in metazoan cells.
  • The precise mechanism of ATR activation by TOPBP1 and ETAA1, including the role of dimerization, is not fully understood.

Purpose of the Study:

  • To investigate the role of TOPBP1 and ETAA1 dimerization in ATR kinase activation and signaling.
  • To elucidate the biochemical mechanism by which TOPBP1 and ETAA1 activate ATR.
  • To determine the functional significance of TOPBP1 and ETAA1 dimerization for genome stability.

Main Methods:

  • Fusion of TOPBP1 and ETAA1 ATR activation domains (AADs) to dimeric tags for in vitro activation assays.
  • Chemical dimerization of modified FKBP tags to induce dimerization of AADs in cells.
  • Analysis of ETAA1 oligomeric complex formation and functional rescue experiments in ETAA1-deficient cells.

Main Results:

  • Fusion to dimeric tags increased the potency of TOPBP1 and ETAA1 AADs in activating ATR in vitro.
  • Induced dimerization of AADs enhanced ATR kinase activation and signaling in cellular models.
  • ETAA1 forms oligomeric complexes, and induced dimerization of a mini-ETAA1 protein rescued cellular defects and suppressed micronuclei formation.

Conclusions:

  • Dimerization of TOPBP1 and ETAA1 is important for optimal ATR signaling.
  • The findings clarify the mechanism of ATR activation and highlight the significance of protein dimerization in DNA damage response pathways.
  • TOPBP1 and ETAA1 dimerization contributes to maintaining genome stability.
Keywords:
ATRATR activation domainDNA damage responseETAA1RPATOPBP1cell cycle checkpointphosphatidylinositol 3-kinase related protein kinasereplication stress response

More Related Videos

Isolation of Atrial Myocytes from Adult Mice08:34

Isolation of Atrial Myocytes from Adult Mice

Published on: July 25, 2019

11.0K
Deciphering the Structural Effects of Activating EGFR Somatic Mutations with Molecular Dynamics Simulation15:05

Deciphering the Structural Effects of Activating EGFR Somatic Mutations with Molecular Dynamics Simulation

Published on: May 20, 2020

9.0K

Related Concept Videos

Activation and Inactivation of G Proteins01:22

Activation and Inactivation of G Proteins

Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high...
8.7K
G-Protein Gated Ion Channels01:21

G-Protein Gated Ion Channels

GPCRs are primarily responsible for our sense of smell, taste, and vision.  The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory...
5.2K
Eukaryotic Transcription Activators02:42

Eukaryotic Transcription Activators

Transcription activators are proteins that promote the transcription of genes from DNA to RNA. In most cases, these proteins contain two separate domains ‒ a domain that binds to DNA and a domain for activating transcription; however, in some cases, a single domain is responsible for both binding and activation of transcription, as seen in the glucocorticoid receptor and MyoD.
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These...
11.9K
The ADP/ATP Carrier Protein01:42

The ADP/ATP Carrier Protein

ADP/ATP carrier or AAC protein is the most abundant carrier protein in the inner mitochondrial membrane. It transports large quantities of ADP and ATP, equivalent to the average human body weight, every day. Among other transporters, ACC protein is one of the best-studied members of the mitochondrial carrier protein family. The ADP/ATP carrier protein comprises two transmembrane helices connected to a loop and a single alpha-helix on the matrix side. It switches between two conformational...
3.7K
Receptor Tyrosine Kinases01:26

Receptor Tyrosine Kinases

Receptor tyrosine kinases or RTKs are membrane-bound receptors that phosphorylate specific tyrosine on protein substrates. RTKs regulate cellular growth, differentiation, survival, and migration. They contain an extracellular ligand binding domain, a transmembrane domain, and a cytosolic tail with intrinsic kinase activity. Several extracellular signaling molecules activate RTKs in one or more ways and relay the signal downstream. Ligands such as platelet-derived growth factor (PDGF) or...
16.2K
GPCRs Regulate Adenylyl Cylase Activity01:09

GPCRs Regulate Adenylyl Cylase Activity

Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of...
6.4K