CDC16 is a core component of the anaphase promoting complex/cyclosome (APC/C), a cell cycle-regulated E3 ubiquitin ligase that controls mitosis and G1 phase progression 1. The APC/C catalyzes formation of Lys-11-linked polyubiquitin chains, with lesser contributions from Lys-48 and Lys-63 linkages, and assembles branched Lys-11/Lys-48-linked chains on target proteins to mediate their degradation 12. CDC16 expression is dynamically regulated in response to cellular stress. Ionizing radiation downregulates CDC16 expression within 1-3 hours, potentially delaying progression of damaged cells through mitosis to allow DNA repair 3. CDC16 repression also occurs following oxidative stress exposure 3. Recently, c-Jun was shown to competitively interact with CDC16, reducing APC complex formation and arresting cells in G1 phase to promote neuroblastoma differentiation 4. Clinically, CDC16 deletions have been associated with neurodevelopmental disorders when deleted alongside CHAMP1 on chromosome 13, causing borderline intellectual disability with minimal quality-of-life impact 5. CDC16 represents a therapeutic target, as its inhibition via protein-protein interactions can suppress cell cycle progression and induce cellular differentiation in cancer contexts 4.