Extended Data Figure 5 ∣. WDR5 binds near the catalytic core of the APC/C.

a, WDR5 forms BMB(1,4-bismaleimdobutane)-dependent crosslinks with APC2, APC11, and CDC20. APC/C^CDC20 was affinity purified from prometaphase-arrested HeLa cells and incubated with recombinant WDR5 or WDR5^ΔWIN prior to addition of crosslinker. Crosslinked APC/C subunits were detected by SDS-PAGE and Western blotting using specific antibodies. This experiment was performed two independent times with similar results.

b, In vitro translation binding assays reveal that APC2 directly interacts with recombinant WDR5. MBP-tagged WDR5 or WDR5^ΔWIN were immobilized on amylose resin and incubated with ³⁵S-labeled APC/C subunits produced by in vitro transcription/translation. Bound proteins were detected by SDS-PAGE and autoradiography. APC3 failed to synthesize by in vitro transcription/translation. This experiment was performed once for the full set of APC/C subunits. APC2 binding was validated three independent times.

c, Quantification of autoradiography blot shown in b.