Abstract
ABSTRACT
Centromeres are specialized chromosomal loci that ensure faithful chromosome segregation during mitosis, a function that depends on the precise localization of the histone H3 variant centromere protein A (CENP‐A) within centromeric chromatin. CENP‐A deposition is tightly regulated by assembly factors, including HJURP; however, the complete regulatory network remains incompletely defined. Using CENP‐A immunoprecipitation coupled with mass spectrometry, we identified SET, a multifunctional chromatin‐associated protein involved in transcription and nucleosome assembly, as one of the most enriched proteins in CENP‐A immunoprecipitates, suggesting an association between SET and CENP‐A. Here, we investigated this association and its functional significance. Reciprocal co‐immunoprecipitation assays showed that SET associates with both CENP‐A and HJURP. Immunofluorescence analysis revealed that SET localizes to centromeres and that SET depletion reduces centromeric CENP‐A enrichment. Live‐cell imaging further showed that SET depletion causes chromosome alignment defects and prolonged mitotic arrest. Together, these findings identify SET as a previously unrecognized regulator of the CENP‐A‐HJURP axis and suggest that SET supports proper CENP‐A localization at centromeres and faithful mitotic progression. This study expands our understanding of the regulatory network that maintains centromere identity.