The aim of this study was to identify novel substrates of the FANCcore complex, which inactivation leads to the genetic disorder Fanconi anemia (FA), which associates bone marrow failure, developmental abnormalities and predisposition to cancer. Eight FANC proteins participate in the nuclear FANCcore complex, an E3 ubiquitin-ligase that monoubiquitinates FANCD2 and FANCI in response to replicative stress. Here, we used mass spectrometry to compare proteins from FANCcore complex deficient FA-A and FA-C cells to their ectopically corrected counterparts challenged with hydroxyurea, an inducer of FANCD2 monoubiquitination.
FANCD2 and FANCI appear as the only targets of the FANCcore complex. We identified other proteins post-translationally modified in a FANCA- or FANCC-dependent manner. The majority of these potential targets localizes to the cell membrane. Finally, we demonstrated that (a) the chemokine receptor CXCR5 is neddylated; (b) FANCA, but not FANCC, appears to modulate CXCR5 neddylation through an unknown mechanism; (c) CXCR5 neddylation is involved in targeting the receptor to the cell membrane; and (d) CXCR5 neddylation stimulates cell migration/motility.
Our work has uncovered a pathway involving FANCA in neddylation and cell motility.