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TRIM39 is a MOAP-1-binding protein that stabilizes MOAP-1 through inhibition of its poly-ubiquitination process

San San Lee1, Nai Yang Fu, Sunil K Sukumaran

  • 1Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Singapore 138673, Singapore.

Experimental Cell Research
|December 23, 2008
PubMed

Insights

Tripartite Motif 39 (TRIM39) stabilizes the short-lived protein MOAP-1 by inhibiting its degradation. This stabilization enhances apoptosis signaling, sensitizing cells to chemotherapy drugs like etoposide.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Bax is a pro-apoptotic protein regulating mitochondrial factor release.
  • MOAP-1 interacts with Bax during apoptosis and is rapidly degraded by the ubiquitin-proteasome system.
  • Factors controlling MOAP-1 stability were previously unknown.

Purpose of the Study:

  • To identify cellular factors that regulate MOAP-1 stability.
  • To investigate the role of TRIM39 in apoptosis signaling.

Main Methods:

  • Co-immunoprecipitation to identify MOAP-1 binding proteins.
  • Western blotting to assess protein stability and ubiquitination.
  • Cell viability assays to determine apoptosis sensitivity.
  • Mitochondrial assays to measure cytochrome c release.

Main Results:

  • TRIM39 was identified as a MOAP-1 binding protein.
  • TRIM39 inhibits MOAP-1 poly-ubiquitination, extending its half-life.
  • TRIM39 sensitizes cells to etoposide-induced apoptosis.
  • TRIM39 promotes cytochrome c release from mitochondria.

Conclusions:

  • TRIM39 stabilizes MOAP-1, thereby promoting apoptosis.
  • TRIM39 enhances apoptosis signaling through MOAP-1 stabilization, impacting cellular sensitivity to chemotherapy.

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