Molecular Cell
Volume 65, Issue 2, 19 January 2017, Pages 247-259
Journal home page for Molecular Cell

Article
Mechanism of Ubiquitination and Deubiquitination in the Fanconi Anemia Pathway

https://doi.org/10.1016/j.molcel.2016.11.005Get rights and content
Under an Elsevier user license
open archive

Highlights

  • Reconstitution of the Fanconi anemia (FA) pathway using recombinant proteins

  • FANCB dimer coordinates FANCD2:FANCI monoubiquitination by two FANCL RING-ligases

  • FANCC and FANCE provide FANCL specificity toward DNA-bound FANCD2:FANCI dimers

  • Deubiquitination of FANCD2:FANCI by USP1:UAF1 occurs only when DNA is removed

Summary

Monoubiquitination and deubiquitination of FANCD2:FANCI heterodimer is central to DNA repair in a pathway that is defective in the cancer predisposition syndrome Fanconi anemia (FA). The “FA core complex” contains the RING-E3 ligase FANCL and seven other essential proteins that are mutated in various FA subtypes. Here, we purified recombinant FA core complex to reveal the function of these other proteins. The complex contains two spatially separate FANCL molecules that are dimerized by FANCB and FAAP100. FANCC and FANCE act as substrate receptors and restrict monoubiquitination to the FANCD2:FANCI heterodimer in only a DNA-bound form. FANCA and FANCG are dispensable for maximal in vitro ubiquitination. Finally, we show that the reversal of this reaction by the USP1:UAF1 deubiquitinase only occurs when DNA is disengaged. Our work reveals the mechanistic basis for temporal and spatial control of FANCD2:FANCI monoubiquitination that is critical for chemotherapy responses and prevention of Fanconi anemia.

Keywords

Fanconi anemia
core complex
monoubiquitination
RING E3
deubiquitination
FANCD2
FANCB
DNA repair
enzyme mechanism

Cited by (0)

5

Lead Contact