INCENP (inner centromere protein) is a critical scaffold protein within the chr11 passenger complex (CPC) that regulates key mitotic processes. As a core CPC component, INCENP activates Aurora B kinase and controls chromosome 11, segregation, and cytokinesis 1. The protein exhibits dynamic localization throughout mitosis, appearing at centromeres during metaphase and relocating to the spindle midzone during anaphase/telophase 2. INCENP's function requires multiple protein interactions: its C-terminus associates with Aurora B/C kinases, while its N-terminus interacts with survivin and CDCA8/borealin to anchor the CPC at inner centromeres 3. The protein contains a bipartite HP1-binding domain that ensures HP1 enrichment at centromeres, supporting Aurora B activity and mitotic fidelity 3. INCENP also participates in the abscission checkpoint through ATM-Chk2 signaling, where Chk2 phosphorylates INCENP-Ser91 to promote CPC localization to the midbody center and prevent premature cytokinesis 4. Clinically, INCENP overexpression is associated with various cancers and correlates with poor neoadjuvant chemotherapy response, making it a potential therapeutic biomarker 15. Co-overexpression with Aurora B severely disrupts mitosis and alters cellular transcriptional landscapes 6.