Nucleoporin NUP153 guards genome integrity by promoting nuclear import of 53BP1

Cell Death Differ. 2012 May;19(5):798-807. doi: 10.1038/cdd.2011.150. Epub 2011 Nov 11.

Abstract

53BP1 is a mediator of DNA damage response (DDR) and a tumor suppressor whose accumulation on damaged chromatin promotes DNA repair and enhances DDR signaling. Using foci formation of 53BP1 as a readout in two human cell lines, we performed an siRNA-based functional high-content microscopy screen for modulators of cellular response to ionizing radiation (IR). Here, we provide the complete results of this screen as an information resource, and validate and functionally characterize one of the identified 'hits': a nuclear pore component NUP153 as a novel factor specifically required for 53BP1 nuclear import. Using a range of cell and molecular biology approaches including live-cell imaging, we show that knockdown of NUP153 prevents 53BP1, but not several other DDR factors, from entering the nuclei in the newly forming daughter cells. This translates into decreased IR-induced 53BP1 focus formation, delayed DNA repair and impaired cell survival after IR. In addition, NUP153 depletion exacerbates DNA damage caused by replication stress. Finally, we show that the C-terminal part of NUP153 is required for effective 53BP1 nuclear import, and that 53BP1 is imported to the nucleus through the NUP153-importin-β interplay. Our data define the structure-function relationships within this emerging 53BP1-NUP153/importin-β pathway and implicate this mechanism in the maintenance of genome integrity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Cell Nucleus / metabolism*
  • Genome, Human / genetics*
  • HeLa Cells
  • Humans
  • Immunoblotting
  • Immunoprecipitation
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Nuclear Pore Complex Proteins / genetics
  • Nuclear Pore Complex Proteins / metabolism*
  • Protein Binding / genetics
  • RNA Interference / physiology
  • Tumor Suppressor p53-Binding Protein 1

Substances

  • Intracellular Signaling Peptides and Proteins
  • NUP153 protein, human
  • Nuclear Pore Complex Proteins
  • TP53BP1 protein, human
  • Tumor Suppressor p53-Binding Protein 1