Supplementary Figure 4. Characterization of the ubiquitination reactions under initial velocity conditions used to determine the apparent inhibitory constants of EMI1 variants. 15 Supplementary Figure 5. EMI1 is a tight binding inhibitor of both substrate ubiquitination and Ub chain forming activities of the APC/C CDH1 .
Protein ubiquitination involves E1, E2, and E3 trienzyme cascades. E2 and RING E3 enzymes often collaborate to first prime a substrate with a single ubiquitin (UB) and then achieve different forms of polyubiquitination: multiubiquitination of several sites and elongation of linkage-specific UB chains. Here, cryo-EM and biochemistry show that the human E3… (More)
The Anaphase Promoting Complex/Cyclosome (APC/C) is a ~1.5 MDa multiprotein E3 ligase enzyme that regulates cell division by promoting timely ubiquitin-mediated proteolysis of key cell cycle regulatory proteins. Inhibition of human APC/C CDH1 during interphase by Early Mitotic Inhibitor 1 (EMI1) is essential for accurate coordination of DNA synthesis and… (More)
The anaphase-promoting complex/cyclosome bound to CDC20 (APC/C CDC20) initiates anaphase by ubiquitylating B-type cyclins and securin. During chromosome bi-orientation, CDC20 assembles with MAD2, BUBR1 and BUB3 into a mitotic checkpoint complex (MCC) which inhibits substrate recruitment to the APC/C. APC/C activation depends on MCC disassembly, which has… (More)