BRCA1-independent ubiquitination of FANCD2

Mol Cell. 2003 Jul;12(1):247-54. doi: 10.1016/s1097-2765(03)00281-8.

Abstract

Monoubiquitination of the FANCD2 protein is a key step in the Fanconi anemia (FA) tumor suppressor pathway, coinciding with this molecule's accumulation at sites of genome damage. Strong circumstantial evidence points to a requirement for the BRCA1 gene product in this step. Here, we show that the purified BRCA1/BARD1 complex, together with E1 and UbcH5a, is sufficient to reconstitute the monoubiquitination of FANCD2 in vitro. Although siRNA-mediated knockdown of BRCA1 in human cells results in defective targeting of FANCD2 to sites of DNA damage, it does not lead to a defect in FANCD2 ubiquitination. Furthermore, ablation of the RING finger domains of either BRCA1 or BARD1 in the chicken B cell line DT40 also leaves FANCD2 modification intact. Consequently, while BRCA1 affects the accumulation of FANCD2 at sites of DNA damage, BRCA1/BARD1 E3 ligase activity is not essential for the monoubiquitination of FANCD2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • BRCA1 Protein / antagonists & inhibitors
  • BRCA1 Protein / genetics
  • BRCA1 Protein / metabolism*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Cell-Free System / drug effects
  • Cell-Free System / metabolism
  • DNA Damage / genetics*
  • Fanconi Anemia / enzymology*
  • Fanconi Anemia / genetics
  • Fanconi Anemia Complementation Group D2 Protein
  • Gene Expression Regulation, Neoplastic / genetics
  • HeLa Cells
  • Humans
  • Iron-Binding Proteins*
  • Ligases / genetics
  • Ligases / metabolism
  • Mutation / genetics
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Protein Structure, Tertiary / genetics
  • RNA, Small Interfering / pharmacology
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism*
  • Ubiquitin / metabolism*
  • Ubiquitin-Conjugating Enzymes*
  • Ubiquitin-Protein Ligases*

Substances

  • BRCA1 Protein
  • Carrier Proteins
  • FANCD2 protein, human
  • Fanconi Anemia Complementation Group D2 Protein
  • Iron-Binding Proteins
  • Nuclear Proteins
  • RNA, Small Interfering
  • Tumor Suppressor Proteins
  • Ubiquitin
  • UBE2D1 protein, human
  • Ubiquitin-Conjugating Enzymes
  • BARD1 protein, human
  • Ubiquitin-Protein Ligases
  • Ligases