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Updated: Jul 15, 2025

In Vitro Analysis of E3 Ubiquitin Ligase Function
06:06

In Vitro Analysis of E3 Ubiquitin Ligase Function

Published on: May 14, 2021

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Structure and activation of the RING E3 ubiquitin ligase TRIM72 on the membrane

Si Hoon Park1,2, Juhyun Han1, Byung-Cheon Jeong1,3

  • 1Department of Life Sciences, Korea University, Seoul, South Korea.

Nature Structural & Molecular Biology
|September 28, 2023
PubMed

Insights

Defects in plasma membrane repair are linked to muscle and heart diseases. This study reveals how Tripartite Motif-containing protein 72 (TRIM72) assembles on damaged membranes, offering insights into E3 ligase regulation and potential therapeutic strategies.

Area of Science:

  • Biochemistry
  • Structural Biology
  • Cell Biology

Background:

  • Defects in plasma membrane repair are implicated in human muscle and heart diseases.
  • Tripartite Motif-containing protein 72 (TRIM72), also known as mitsugumin 53 (MG53), is crucial for rapid vesicle nucleation at membrane damage sites.
  • The precise molecular mechanisms governing TRIM72's function in membrane repair are not fully understood.

Purpose of the Study:

  • To elucidate the molecular mechanisms of TRIM72 in plasma membrane repair.
  • To present the structural model of Mus musculus TRIM72, a complete TRIM E3 ubiquitin ligase.
  • To investigate the role of membrane interaction in TRIM72's assembly and activity.

Main Methods:

  • X-ray crystallography to determine the structure of TRIM72.
  • Cryogenic electron tomography and subtomogram averaging to visualize higher-order TRIM72 assemblies on phospholipid bilayers.
  • Biochemical assays to assess TRIM72-membrane interactions and ubiquitination activity.

Main Results:

  • The interaction between TRIM72 and phosphatidylserine-enriched membranes is essential for its oligomeric assembly and E3 ubiquitin ligase activity.
  • A higher-order model of TRIM72 assembly on phospholipid bilayers was elucidated using cryogenic electron tomography.
  • A comprehensive molecular model of TRIM72 was developed, highlighting domain cooperation in higher-order assemblies for regulating RING-type E3 ligases.

Conclusions:

  • The study provides a fundamental structural and mechanistic basis for understanding TRIM E3 ligases.
  • Findings offer insights into how TRIM72 regulates E3 ligase activity through oligomeric assembly on damaged membranes.
  • The research has significant therapeutic implications for diseases associated with impaired plasma membrane repair.

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