Chen Xuemin, Crawford McKenna C, Xiong Ying, Shaik Anver Basha, Suazo Kiall F, Penkalapati Manini S, Williams Joycelyn H, Andressen Thorkell, Swenson Rolf E, Meier Jordan L
Chemical Biology Laboratory, National Cancer Institute, Frederick, MD, USA.
Chemistry and Synthesis Center, National Heart Lung and Blood Institute, Bethesda, MD, USA.
bioRxiv. 2024 May 5:2024.05.03.592353. doi: 10.1101/2024.05.03.592353.
The transcriptional coactivators EP300 and CREBBP are critical regulators of gene expression that share high sequence identity but exhibit non-redundant functions in basal and pathological contexts. Here, we report the development of a bifunctional small molecule, MC-1, capable of selectively degrading EP300 over CREBBP. Using a potent aminopyridine-based inhibitor of the EP300/CREBBP catalytic domain in combination with a VHL ligand, we demonstrate that MC-1 preferentially degrades EP300 in a proteasome-dependent manner. Mechanistic studies reveal that selective degradation cannot be predicted solely by target engagement or ternary complex formation, suggesting additional factors govern paralogue-specific degradation. MC-1 inhibits cell proliferation in a subset of cancer cell lines and provides a new tool to investigate the non-catalytic functions of EP300 and CREBBP. Our findings expand the repertoire of EP300/CREBBP-targeting chemical probes and offer insights into the determinants of selective degradation of highly homologous proteins.
转录共激活因子EP300和CREBBP是基因表达的关键调节因子，它们具有高度的序列同一性，但在基础和病理环境中发挥非冗余功能。在此，我们报告了一种双功能小分子MC-1的研发，它能够选择性地降解EP300而不是CREBBP。通过将一种基于氨基吡啶的强效EP300/CREBBP催化结构域抑制剂与一种VHL配体结合使用，我们证明MC-1以蛋白酶体依赖的方式优先降解EP300。机制研究表明，选择性降解不能仅通过靶点结合或三元复合物形成来预测，这表明还有其他因素决定了旁系同源物特异性降解。MC-1在一部分癌细胞系中抑制细胞增殖，并为研究EP300和CREBBP的非催化功能提供了一种新工具。我们的研究结果扩展了靶向EP300/CREBBP的化学探针的种类，并为深入了解高度同源蛋白质选择性降解的决定因素提供了见解。
