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Selectional and mutational scope of peptides sequestering the Jun-Fos coiled-coil domain

Urs B Hagemann1, Jody M Mason, Kristian M Müller

  • 1Institute for Biology III, Albert-Ludwigs-University of Freiburg, Schaenzlestrass 1, D-79104 Freiburg, Germany.

Journal of Molecular Biology
|July 1, 2008
PubMed

Insights

Researchers identified novel peptides that disrupt the activator protein-1 (AP-1) complex, a key player in tumorigenesis. These peptides show high affinity for cFos, offering potential therapeutic strategies against cancer.

Area of Science:

  • Molecular Biology
  • Biochemistry
  • Cancer Research

Background:

  • The activator protein-1 (AP-1) complex is integral to cellular signaling pathways and implicated in tumorigenesis.
  • AP-1's role in cancer makes it a significant therapeutic target.
  • Understanding and disrupting AP-1 complex formation is crucial for developing targeted cancer therapies.

Purpose of the Study:

  • To identify and characterize peptides capable of disrupting the cFos/cJun interaction within the AP-1 complex.
  • To compare the efficacy of peptides selected via phage display against those identified through in vivo protein-fragment complementation assays (PCA).
  • To evaluate the potential of these peptides as therapeutic agents and tools for systems biology.

Main Methods:

  • Phage display screening was employed to select peptides targeting the cFos coiled-coil domain, aiming to disrupt AP-1 complex formation.
  • Protein-fragment complementation assay (PCA) was used to compare the inhibitory effects of selected peptides.
  • Thermal shift assays (T(m)) measured peptide-cFos binding affinity.
  • Gel shift assays assessed the impact of peptides on AP-1 DNA binding activity.

Main Results:

  • Phage display identified a highly effective peptide, JunW(Ph1), with superior affinity to cFos compared to wild-type cJun.
  • JunW(Ph1) demonstrated significantly greater disruption of the cFos/cJun interaction in PCA growth assays than the PCA-selected peptide JunW.
  • All identified inhibitory peptides effectively interfered with AP-1's DNA binding capabilities.
  • The study improved a 'bZIP coiled-coil interaction prediction algorithm' using the identified peptide sequences.

Conclusions:

  • Novel peptides, particularly JunW(Ph1), efficiently disrupt the AP-1 complex by targeting cFos.
  • These peptides exhibit high affinity and effectively inhibit AP-1 function, including DNA binding.
  • The findings provide valuable tools for analytical and biomedical applications and advance systems biology through improved protein interaction prediction.

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