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Essential role of CED-4 oligomerization in CED-3 activation and apoptosis

X Yang1, H Y Chang, D Baltimore

  • 1Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

Science (New York, N.Y.)
|August 28, 1998
PubMed

Insights

Apoptosis control is vital for development and cancer prevention. In C. elegans, CED-4 oligomerization activates CED-3 caspase, a process inhibited by CED-9, revealing a key apoptotic regulatory mechanism.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Genetics

Background:

  • Apoptosis regulation is crucial for development and cancer prevention.
  • In Caenorhabditis elegans, the pro-apoptotic protein CED-4 activates the CED-3 caspase.
  • The Bcl-2-like protein CED-9 inhibits CED-4 activity through protein-protein interactions.

Purpose of the Study:

  • To elucidate the mechanism by which CED-4 controls CED-3 caspase activation.
  • To investigate the role of CED-4 oligomerization in apoptosis.
  • To understand how CED-9 binding regulates CED-4 function.

Main Methods:

  • Studied protein-protein interactions in vitro and in cells.
  • Investigated CED-4 oligomerization using biochemical and cellular assays.
  • Utilized genetic mutations to assess the impact on CED-4 function and apoptosis.

Main Results:

  • CED-4 protein oligomerization was observed in cells and in vitro.
  • CED-4 oligomerization induced proximity of CED-3 zymogen molecules, promoting caspase activation.
  • CED-4 oligomerization competed with CED-4:CED-9 interaction, and mutations abolishing oligomerization inactivated CED-4's ability to activate CED-3.

Conclusions:

  • CED-4 oligomerization is the mechanism that induces CED-3 proximity and activates the caspase.
  • CED-9 inhibits apoptosis by preventing CED-4 oligomerization.
  • This study reveals a novel regulatory mechanism for apoptosis control involving protein oligomerization and competitive binding.

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