{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n KDM4A (also known as JMJD2A) is a Jumonji‐C domain–containing histone demethylase that removes di‐ and tri‐methyl groups from histone H3 lysine 9 (H3K9me2/3) and lysine 36 (H3K36me2/3), thereby modulating chromatin structure and gene expression. In the context of exhausted CD8 T cells, epigenetic remodeling mediated by enzymes such as KDM4A is thought to contribute to the establishment or maintenance of dysfunctional transcriptional programs that underlie immune exhaustion."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n In addition to its role in shaping immune cell states, KDM4A is involved in the response to DNA damage. Under genotoxic stress, KDM4A binds specific methylated histone marks (for example, H4K20me2), but is targeted for ubiquitin‐dependent proteasomal degradation via the actions of RNF8/RNF168. This removal appears to facilitate proper recruitment of the repair factor 53BP1—and therefore efficient double‐strand break repair—as well as to influence homologous recombination efficiency."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Structural studies have elucidated how KDM4A recognizes its histone substrates through a specialized active‐site pocket, ensuring methylation state selectivity; these insights into substrate binding underlie its function in demethylating both repressive and activating chromatin marks."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Moreover, KDM4A participates in transcriptional regulation by associating with key cell cycle and transcriptional coregulatory complexes. For example, its interactions with the retinoblastoma protein and class I histone deacetylases, as well as with the N‐CoR complex, contribute to the repression of E2F‐regulated promoters, impacting both cell proliferation and oncogenesis."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n KDM4A also functions as a coactivator in certain contexts. It has been implicated in androgen receptor–mediated transcription in prostate cancer and, through an adaptor role, participates in signaling cascades that promote Akt activation—thereby linking epigenetic regulation with signal transduction pathways that drive tumor progression."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Collectively, the multifaceted functions of KDM4A in modulating histone methylation, regulating DNA repair factor access, and forming transcriptional regulatory complexes underscore its role as an integrator of epigenetic signals that influence both immune cell fate—as in exhausted CD8 T cells—and oncogenic processes.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Omar Khan, Josephine R Giles, Sierra McDonald, et al. 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