Activation of the main DNA interstrand crosslink repair pathway in higher eukaryotes requires mono-ubiquitination of FANCI and FANCD2 by FANCL, the E3 ligase subunit of the Fanconi anemia core complex. FANCI and FANCD2 form a stable complex; however, the molecular basis of their ubiquitination is ill defined. FANCD2 mono-ubiquitination by FANCL is stimulated by the presence of the FANCB and FAAP100 core complex components, through an unknown mechanism. How FANCI mono-ubiquitination is achieved remains unclear. Here, we use structural electron microscopy, combined with crosslink-coupled mass spectrometry, to find that FANCB, FANCL, and FAAP100 form a dimer of trimers, containing two FANCL molecules that are ideally poised to target both FANCI and FANCD2 for mono-ubiquitination. The FANCC-FANCE-FANCF subunits bridge between FANCB-FANCL-FAAP100 and the FANCI-FANCD2 substrate. A transient interaction with FANCC-FANCE-FANCF alters the FANCI-FANCD2 configuration, stabilizing the dimerization interface. Our data provide a model to explain how equivalent mono-ubiquitination of FANCI and FANCD2 occurs.
|Titolo:||The FA Core Complex Contains a Homo-dimeric Catalytic Module for the Symmetric Mono-ubiquitination of FANCI-FANCD2|
SWUEC, PAOLO (Primo)
|Parole Chiave:||cryo-electron microscopy; DNA repair; Fanconi anemia; interstrand crosslink; mono-ubiquitination; ubiquitin ligase; Amino Acid Sequence; Chromatography, High Pressure Liquid; DNA-Binding Proteins; Dimerization; Fanconi Anemia Complementation Group D2 Protein; Fanconi Anemia Complementation Group Proteins; Humans; Mass Spectrometry; Microscopy, Electron; Protein Multimerization; Protein Structure, Tertiary; Substrate Specificity; Ubiquitination; Biochemistry, Genetics and Molecular Biology (all)|
|Settore Scientifico Disciplinare:||Settore BIO/10 - Biochimica|
|Data di pubblicazione:||17-gen-2017|
|Digital Object Identifier (DOI):||10.1016/j.celrep.2016.11.013|
|Appare nelle tipologie:||01 - Articolo su periodico|