On the regulation, function, and localization of the DNA-dependent ATPase PICH

Chromosoma. 2012 Aug;121(4):395-408. doi: 10.1007/s00412-012-0370-0. Epub 2012 Apr 25.

Abstract

The putative chromatin remodeling enzyme Plk1-interacting checkpoint helicase (PICH) was discovered as an interaction partner and substrate of the mitotic kinase Plk1. During mitosis PICH associates with centromeres and kinetochores and, most interestingly, constitutes a robust marker for ultrafine DNA bridges (UFBs) that connect separating chromatids in anaphase cells. The precise roles of PICH remain to be clarified. Here, we have used antibody microinjection and siRNA-rescue experiments to study PICH function and localization during M phase progression, with particular emphasis on the role of the predicted ATPase domain and the regulation of PICH localization by Plk1. We show that interference with PICH function results in chromatin bridge formation and micronucleation and that ATPase activity is critical for PICH function. Interestingly, an intact ATPase domain of PICH is required for prevention of chromatin bridge formation but not for UFB resolution, and quantitative analyses of UFB and chromatin bridge frequencies suggest that these structures are of different etiologies. We also show that the ATPase activity of PICH is required for temporal and spatial control of PICH localization to chromatin and that Plk1 likely controls PICH localization through phosphorylation of proteins distinct from PICH itself. This work strengthens the view that PICH is an important, Plk1-regulated enzyme, whose ATPase activity is essential for maintenance of genome integrity. Although not required for the spindle assembly checkpoint, PICH is clearly important for faithful chromosome segregation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / genetics*
  • Adenosine Triphosphatases / metabolism
  • Anaphase / genetics
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cell Division
  • Chromatin / genetics
  • Chromatin / metabolism
  • Chromosome Segregation*
  • DNA Helicases / genetics*
  • DNA Helicases / metabolism
  • Gene Expression Regulation
  • HeLa Cells
  • Humans
  • Kinetochores / metabolism
  • Mitosis
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Spindle Apparatus / metabolism

Substances

  • Cell Cycle Proteins
  • Chromatin
  • Proto-Oncogene Proteins
  • RNA, Small Interfering
  • Protein-Serine-Threonine Kinases
  • polo-like kinase 1
  • Adenosine Triphosphatases
  • DNA Helicases