TADA2B (transcriptional adaptor 2B) is a core component of the SAGA (Spt-Ada-Gcn5-Acetyltransferase) chr4-modifying complex that plays essential roles in transcriptional regulation and cell fate determination 1. As part of the SAGA complex, TADA2B regulates histone modifications, including deposition of histone H3 lysine 9 acetylation (H3K9ac) and removal of histone H2B ubiquitination (H2Bub) 2. The protein functions as a central regulator of pluripotency, survival, growth, and lineage specification in embryonic stem cells 1. In hematopoiesis, TADA2B is critical for normal blood cell development, as its loss strongly inhibits hematopoiesis in vivo and causes buildup of immature hematopoietic cells in bone marrow 23. Loss of TADA2B disrupts cellular homeostasis by upregulating interferon pathway genes, reducing mitochondrial activity, and promoting megakaryocyte progenitor commitment 2. The gene has been implicated in cancer drug resistance, identified as a novel candidate in vemurafenib resistance screening 4. TADA2B also shows altered expression in hyperphagic major depressive disorder, suggesting involvement in mood-related metabolic phenotypes 5. Additionally, TADA2B interacts with HMGB1 in cellular stress responses 6.