SMK-1/PPH-4.1-mediated silencing of the CHK-1 response to DNA damage in early C. elegans embryos

J Cell Biol. 2007 Oct 8;179(1):41-52. doi: 10.1083/jcb.200705182. Epub 2007 Oct 1.

Abstract

During early embryogenesis in Caenorhabditis elegans, the ATL-1-CHK-1 (ataxia telangiectasia mutated and Rad3 related-Chk1) checkpoint controls the timing of cell division in the future germ line, or P lineage, of the animal. Activation of the CHK-1 pathway by its canonical stimulus DNA damage is actively suppressed in early embryos so that P lineage cell divisions may occur on schedule. We recently found that the rad-2 mutation alleviates this checkpoint silent DNA damage response and, by doing so, causes damage-dependent delays in early embryonic cell cycle progression and subsequent lethality. In this study, we report that mutations in the smk-1 gene cause the rad-2 phenotype. SMK-1 is a regulatory subunit of the PPH-4.1 (protein phosphatase 4) protein phosphatase, and we show that SMK-1 recruits PPH-4.1 to replicating chromatin, where it silences the CHK-1 response to DNA damage. These results identify the SMK-1-PPH-4.1 complex as a critical regulator of the CHK-1 pathway in a developmentally relevant context.

Publication types

  • Research Support, N.I.H., Extramural
  • Retracted Publication

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / enzymology
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism
  • Caenorhabditis elegans Proteins / physiology*
  • Checkpoint Kinase 1
  • Chromatin / metabolism
  • DNA Damage*
  • Embryo, Nonmammalian / enzymology
  • Embryonic Development / genetics
  • Enzyme Activation
  • Longevity / genetics
  • Molecular Sequence Data
  • Mutation
  • Phosphoprotein Phosphatases / genetics
  • Phosphoprotein Phosphatases / metabolism
  • Phosphoprotein Phosphatases / physiology*
  • Protein Kinases / genetics
  • Protein Kinases / metabolism*
  • Protein Subunits / genetics
  • Protein Subunits / metabolism
  • Protein Subunits / physiology

Substances

  • Caenorhabditis elegans Proteins
  • Chromatin
  • Protein Subunits
  • Protein Kinases
  • Checkpoint Kinase 1
  • chk-1 protein, C elegans
  • Phosphoprotein Phosphatases
  • SMK-1 protein, C elegans
  • protein phosphatase 4