Figure 1.

(a) Illustration of Fanconi anaemia core-complex mediated ubiquitination of FANCD2 with the 11 proteins used in the inhibitor assay, and (b) read out of core complex-mediated ubiquitination of FANCD2 in the proximity assay. When b-ubiquitin is covalently conjugated to GST-FANCD2 they bind the streptavidin-coated donor beads and the anti-GST coated acceptor beads respectively, hence bringing the two bead types into close proximity. When the two bead types are in close proximity – due to FANCD2 mono-ubiquitination – excitation of the donor bead at 680 nm results in the transfer of an oxygen singlet to the acceptor bead. The acceptor bead then emits detectable light between 520–620 nm. Figure created with BioRender.