• Register
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.


Leaving Community

Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.


The anaphase promoting complex contributes to the degradation of the S. cerevisiae telomerase recruitment subunit Est1p.

Telomerase is a multi-subunit enzyme that reverse transcribes telomere repeats onto the ends of linear eukaryotic chromosomes and is therefore critical for genome stability. S. cerevisiae telomerase activity is cell-cycle regulated; telomeres are not elongated during G1 phase. Previous work has shown that Est1 protein levels are low during G1 phase, preventing telomerase complex assembly. However, the pathway targeting Est1p for degradation remained uncharacterized. Here, we show that Est1p stability through the cell cycle mirrors that of Clb2p, a known target of the Anaphase Promoting Complex (APC). Indeed, Est1p is stabilized by mutations in both essential and non-essential components of the APC. Mutations of putative Destruction boxes (D-boxes), regions shown to be important for recognition of known APC substrates, stabilize Est1p, suggesting that Est1p is likely to be targeted for degradation directly by the APC. However, we do not detect degradation or ubiquitination of recombinant Est1p by the APC in vitro, suggesting either that the recombinant protein lacks necessary post-translational modification and/or conformation, or that the APC affects Est1p degradation by an indirect mechanism. Together, these studies shed light on the regulation of yeast telomerase assembly and demonstrate a new connection between telomere maintenance and cell cycle regulation pathways.

Pubmed ID: 23372810


  • Ferguson JL
  • Chao WC
  • Lee E
  • Friedman KL


PloS one

Publication Data

February 1, 2013

Associated Grants

  • Agency: NIDDK NIH HHS, Id: DK058404
  • Agency: NIGMS NIH HHS, Id: GM080393
  • Agency: NCI NIH HHS, Id: P30 CA68485

Mesh Terms

  • Amino Acid Sequence
  • Anaphase-Promoting Complex-Cyclosome
  • Animals
  • Cdh1 Proteins
  • G1 Phase
  • Mutation
  • Protein Stability
  • Proteolysis
  • Recombinant Proteins
  • S Phase
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Telomerase
  • Ubiquitin-Protein Ligase Complexes
  • Ubiquitination