LCD1: an essential gene involved in checkpoint control and regulation of the MEC1 signalling pathway in Saccharomyces cerevisiae

EMBO J. 2000 Nov 1;19(21):5801-12. doi: 10.1093/emboj/19.21.5801.


We identified YDR499W as a Saccharomyces cerevisiae open reading frame with homology to several checkpoint proteins, including S. cerevisiae Rfc5p and Schizosaccharomyces pombe Rad26. Disruption of YDR499W (termed LCD1) results in lethality that is rescued by increasing cellular deoxyribonucleotide levels. Cells lacking LCD1 are very sensitive to a range of DNA-damaging agents, including UV irradiation, and to the inhibition of DNA replication. LCD1 is necessary for the phosphorylation and activation of Rad53p in response to DNA damage or DNA replication blocks, and for Chk1p activation in response to DNA damage. LCD1 is also required for efficient DNA damage-induced phosphorylation of Rad9p and for the association of Rad9p with the FHA2 domain of Rad53p after DNA damage. In addition, cells lacking LCD1 are completely defective in the G(1)/S and G(2)/M DNA damage checkpoints. Finally, we reveal that endogenous Mec1p co-immunoprecipitates with Lcd1p both before and after treatment with DNA-damaging agents. These results indicate that Lcd1p is a pivotal checkpoint regulator, involved in both the essential and checkpoint functions of the Mec1p pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Amino Acid Sequence
  • Cell Cycle
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Checkpoint Kinase 2
  • DNA Damage
  • DNA Repair / genetics
  • DNA Replication
  • Fungal Proteins / genetics*
  • Fungal Proteins / metabolism
  • Genes, Fungal*
  • Intracellular Signaling Peptides and Proteins
  • Molecular Sequence Data
  • Phosphoproteins*
  • Protein Kinases / genetics
  • Protein Kinases / metabolism
  • Protein-Serine-Threonine Kinases*
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins*
  • Schizosaccharomyces / genetics
  • Schizosaccharomyces pombe Proteins*
  • Sequence Homology, Amino Acid


  • Adaptor Proteins, Signal Transducing
  • Cell Cycle Proteins
  • Fungal Proteins
  • Intracellular Signaling Peptides and Proteins
  • LCD1 protein, S cerevisiae
  • Phosphoproteins
  • Saccharomyces cerevisiae Proteins
  • Schizosaccharomyces pombe Proteins
  • rad26 protein, S pombe
  • rad9 protein
  • Protein Kinases
  • Checkpoint Kinase 2
  • MEC1 protein, S cerevisiae
  • Protein-Serine-Threonine Kinases
  • RAD53 protein, S cerevisiae