Related Experiment Video

Updated: Jun 23, 2026

Identifying the Effects of BRCA1 Mutations on Homologous Recombination using Cells that Express Endogenous Wild-type BRCA1
08:53

Identifying the Effects of BRCA1 Mutations on Homologous Recombination using Cells that Express Endogenous Wild-type BRCA1

Published on: February 17, 2011

Characterization of cancer-linked BRCA1-BRCT missense variants and their interaction with phosphoprotein targets

Ioannis Drikos1, George Nounesis, Constantinos E Vorgias

  • 1Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistimiopolis-Zographou, 15701 Athens, Hellas.

Proteins
|May 20, 2009
PubMed

Insights

Five BRCA1 BRCT domain mutations destabilize protein structure and impair binding to phosphopeptides, impacting DNA repair and cell cycle control in breast cancer.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Structural Biology

Background:

  • BRCA1 is a crucial tumor suppressor protein involved in DNA repair and cell cycle regulation.
  • Mutations in the BRCA1 C-terminal tandem (BRCT) repeats are linked to breast cancer, potentially affecting protein stability and interactions.
  • Understanding these mutations' impact is vital for comprehending BRCA1's role in cancer.

Purpose of the Study:

  • To investigate the structural integrity and protein stability of five pathogenic BRCA1 BRCT domain mutations.
  • To analyze the effect of these mutations on the binding affinity of BRCT to specific phosphopeptides.

Main Methods:

  • Cloning and purification of recombinant wild-type (wt) and mutant BRCT proteins.
  • Biophysical analysis using Circular Dichroism Spectroscopy (CD) and Differential Scanning Microcalorimetry (DSC) to assess secondary structure and thermodynamic stability.
  • Isothermal Titration Calorimetry (ITC) to measure binding capacity with phosphopeptides (pBACH1/BRIP1 and pCtIP).

Main Results:

  • All five BRCT mutants exhibited altered thermal unfolding temperatures and unfolding enthalpies compared to wt BRCA1.
  • The mutations varied in their degree of destabilization, affecting protein stability.
  • Binding affinities to pBACH1/BRIP1 and pCtIP phosphopeptides were significantly altered or abolished in the mutants, indicating disrupted interactions.

Conclusions:

  • Pathogenic mutations in the BRCA1 BRCT domain compromise its structural integrity and thermodynamic stability.
  • These structural changes directly impact the binding capabilities of the BRCT domain to essential phosphopeptide partners.
  • The findings contribute to understanding how BRCA1 mutations lead to dysfunction and potentially cancer development.

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