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Evaluation of Substrate Ubiquitylation by E3 Ubiquitin-ligase in Mammalian Cell Lysates
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Evaluation of Substrate Ubiquitylation by E3 Ubiquitin-ligase in Mammalian Cell Lysates

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Structural basis for substrate recognition and chemical inhibition of oncogenic MAGE ubiquitin ligases

Seung Wook Yang1, Xin Huang1, Wenwei Lin2

  • 1Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN, 38105, USA.

Nature Communications
|October 2, 2020
PubMed

Insights

Scientists uncovered how Testis-restricted melanoma antigen (MAGE) proteins bind cancer targets. This discovery of the MAGE substrate binding cleft and its inhibitors paves the way for new cancer therapies.

Area of Science:

  • Molecular Biology
  • Structural Biology
  • Cancer Research

Background:

  • Testis-restricted melanoma antigen (MAGE) proteins are crucial in cancer development.
  • MAGEs act as adaptors for E3 ubiquitin ligases, targeting tumor suppressors for degradation.
  • Understanding MAGE-substrate interactions is key for developing targeted cancer therapies.

Purpose of the Study:

  • To elucidate the structural basis of substrate recognition by MAGE ubiquitin ligases.
  • To identify potential therapeutic strategies targeting MAGE proteins in cancer.

Main Methods:

  • Biochemical analysis of MAGE-A11 and its substrate PCF11.
  • X-ray crystallography to determine the MAGE-A11:PCF11 complex structure.
  • Chemical screening to identify inhibitors of MAGE-A11:substrate interactions.

Main Results:

  • A conserved substrate binding cleft (SBC) in MAGE proteins was identified.
  • Mutations in the SBC abolished substrate recognition and MAGE-A11's oncogenic function.
  • 4-Aminoquinolines were found to be potent inhibitors of MAGE-A11, exhibiting selective cytotoxicity.

Conclusions:

  • The study reveals the structural mechanism of MAGE-mediated substrate recognition.
  • The identified SBC is essential for MAGE protein function in tumorigenesis.
  • 4-Aminoquinolines represent a promising class of compounds for developing novel cancer therapeutics targeting MAGEs.

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