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Distinct mechanisms control the stability of the related S-phase cyclins Clb5 and Clb6.

Publication ,  Journal Article
Jackson, LP; Reed, SI; Haase, SB
Published in: Molecular and cellular biology
March 2006

The yeast S-phase cyclins Clb5 and Clb6 are closely related proteins that are synthesized late in G1. Although often grouped together with respect to function, Clb5 and Clb6 exhibit differences in their ability to promote S-phase progression. DNA replication is significantly slowed in clb5Delta mutants but not in clb6Delta mutants. We have examined the basis for the differential functions of Clb5 and Clb6 and determined that unlike Clb5, which is stable until mitosis, Clb6 is degraded rapidly at the G1/S border. N-terminal deletions of CLB6 were hyperstabilized, suggesting that the sequences responsible for directing the destruction of Clb6 reside in the N terminus. Clb6 lacks the destruction box motif responsible for the anaphase promoting complex-mediated destruction of Clb5 but contains putative Cdc4 degron motifs in the N terminus. Clb6 was hyperstabilized in cdc34-3 and cdc4-3 mutants at restrictive temperatures and when S/T-P phosphorylation sites in the N terminus were mutated to nonphosphorylatable residues. Efficient degradation of Clb6 requires the activities of both Cdc28 and Pho85. Finally, hyperstabilized Clb6 expressed from the CLB6 promoter rescued the slow S-phase defect exhibited by clb5Delta cells. Taken together, these findings suggest that the SCF(Cdc4) ubiquitin ligase complex regulates Clb6 turnover and that the functional differences exhibited by Clb5 and Clb6 arise from the distinct mechanisms controlling their stability.

Duke Scholars

Published In

Molecular and cellular biology

DOI

EISSN

1098-5549

ISSN

0270-7306

Publication Date

March 2006

Volume

26

Issue

6

Start / End Page

2456 / 2466

Related Subject Headings

  • Ubiquitin-Protein Ligases
  • Ubiquitin-Protein Ligase Complexes
  • Ubiquitin-Conjugating Enzymes
  • Ubiquitin
  • Saccharomyces cerevisiae Proteins
  • S Phase
  • Promoter Regions, Genetic
  • Phosphorylation
  • Peptide Fragments
  • Mutation
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Jackson, L. P., Reed, S. I., & Haase, S. B. (2006). Distinct mechanisms control the stability of the related S-phase cyclins Clb5 and Clb6. Molecular and Cellular Biology, 26(6), 2456–2466. https://doi.org/10.1128/mcb.26.6.2456-2466.2006
Jackson, Leisa P., Steven I. Reed, and Steven B. Haase. “Distinct mechanisms control the stability of the related S-phase cyclins Clb5 and Clb6.Molecular and Cellular Biology 26, no. 6 (March 2006): 2456–66. https://doi.org/10.1128/mcb.26.6.2456-2466.2006.
Jackson LP, Reed SI, Haase SB. Distinct mechanisms control the stability of the related S-phase cyclins Clb5 and Clb6. Molecular and cellular biology. 2006 Mar;26(6):2456–66.
Jackson, Leisa P., et al. “Distinct mechanisms control the stability of the related S-phase cyclins Clb5 and Clb6.Molecular and Cellular Biology, vol. 26, no. 6, Mar. 2006, pp. 2456–66. Epmc, doi:10.1128/mcb.26.6.2456-2466.2006.
Jackson LP, Reed SI, Haase SB. Distinct mechanisms control the stability of the related S-phase cyclins Clb5 and Clb6. Molecular and cellular biology. 2006 Mar;26(6):2456–2466.

Published In

Molecular and cellular biology

DOI

EISSN

1098-5549

ISSN

0270-7306

Publication Date

March 2006

Volume

26

Issue

6

Start / End Page

2456 / 2466

Related Subject Headings

  • Ubiquitin-Protein Ligases
  • Ubiquitin-Protein Ligase Complexes
  • Ubiquitin-Conjugating Enzymes
  • Ubiquitin
  • Saccharomyces cerevisiae Proteins
  • S Phase
  • Promoter Regions, Genetic
  • Phosphorylation
  • Peptide Fragments
  • Mutation