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Mec1 function in the DNA damage response does not require its interaction with Tel2

Carol M Anderson1, Elizabeth H Blackburn

  • 1Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158, USA.

Cell Cycle (Georgetown, Tex.)
|November 26, 2008
PubMed

Insights

The Tel2 protein interacts with PIKKs, crucial for DNA damage response. Surprisingly, a tel2-1 mutation disrupts Tel2

Area of Science:

  • Cellular biology
  • Molecular genetics
  • DNA repair mechanisms

Background:

  • Tel2 protein is essential and conserved across eukaryotes, playing a key role in DNA damage and replication stress responses.
  • Tel2 interacts with PI3-kinase related protein kinases (PIKKs) in various organisms, and its absence destabilizes PIKKs in mammalian cells.
  • Previous studies in Saccharomyces cerevisiae demonstrated Tel2 interaction with Tel1 (yeast ATM kinase), disrupted by the tel2-1 mutation, affecting DNA damage response.

Purpose of the Study:

  • To investigate the interaction between Tel2 and Mec1 (yeast ATR kinase) in Saccharomyces cerevisiae.
  • To determine the effect of the tel2-1 mutation on the Tel2-Mec1 interaction and Mec1 function.
  • To re-evaluate the role of Tel2 in regulating PIKK stability and function.

Main Methods:

  • Yeast two-hybrid assays to study protein-protein interactions.
  • Immunoblotting to assess protein levels.
  • Fluorescence microscopy to observe protein localization at DNA damage sites.

Main Results:

  • Tel2 physically interacts with Mec1 in Saccharomyces cerevisiae.
  • The tel2-1 mutation disrupts the physical interaction between Tel2 and Mec1.
  • Despite reduced levels, Mec1 retains its ability to localize to DNA damage sites and function in signaling.

Conclusions:

  • The Tel2 protein's role extends beyond global PIKK stability regulation.
  • Tel2 exhibits specific and differential regulation of individual PIKKs, including Mec1.
  • These findings necessitate a refined model for Tel2 function in DNA damage and replication stress responses.

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