SUMOylation is a posttranslational modification (PTM) at a lysine residue and is crucial for the proper functions of many proteins, particularly of transcription factors, in various biological processes. Zinc finger homeobox 3 (ZFHX3), also known as AT motif-binding factor 1 (ATBF1), is a large transcription factor that is active in multiple pathological processes, including atrial fibrillation and carcinogenesis, and in circadian regulation and development. We have previously demonstrated that ZFHX3 is SUMOylated at three or more lysine residues. Here, we investigated which enzymes regulate ZFHX3 SUMOylation and whether SUMOylation modulates ZFHX3 stability and function. We found that SUMO1, SUMO2, and SUMO3 each are conjugated to ZFHX3. Multiple lysine residues in ZFHX3 were SUMOylated, but Lys-2806 was the major SUMOylation site, and we also found that it is highly conserved among ZFHX3 orthologs from different animal species. Using molecular analyses, we identified the enzymes that mediate ZFHX3 SUMOylation; these included SUMO1-activating enzyme subunit 1 (SAE1), an E1-activating enzyme; SUMO-conjugating enzyme UBC9 (UBC9), an E2-conjugating enzyme; and protein inhibitor of activated STAT2 (PIAS2), an E3 ligase. Multiple analyses established that both SUMO-specific peptidase 1 (SENP1) and SENP2 deSUMOylate ZFHX3. SUMOylation at Lys-2806 enhanced ZFHX3 stability by interfering with its ubiquitination and proteasomal degradation. Functionally, Lys-2806 SUMOylation enabled ZFHX3-mediated cell proliferation and xenograft tumor growth of the MDA-MB-231 breast cancer cell line. These findings reveal the enzymes involved in, and the functional consequences of, ZFHX3 SUMOylation, insights that may help shed light on ZFHX3's roles in various cellular and pathophysiological processes.

中文翻译：

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在Lys-2806上转录因子ZFHX3的SUMOylation需要SAE1，UBC9和PIAS2，并增强其稳定性和细胞增殖功能。

SUMOylation是赖氨酸残基的翻译后修饰（PTM），对于许多蛋白质，特别是转录因子在各种生物学过程中的正常功能至关重要。锌指同源盒3（ZFHX3），也称为AT基序结合因子1（ATBF1），是一种大转录因子，在多种病理过程中都具有活性，包括心房颤动和致癌作用以及昼夜节律的调控和发展。先前我们已经证明ZFHX3在三个或更多赖氨酸残基上被SUMO化。在这里，我们调查了哪些酶调节ZFHX3 SUMOylation，以及SUMOylation是否调节ZFHX3的稳定性和功能。我们发现SUMO1，SUMO2和SUMO3分别与ZFHX3共轭。ZFHX3中的多个赖氨酸残基被SUMO化，但Lys-2806是主要的SUMO化位点，并且我们还发现，在来自不同动物物种的ZFHX3直系同源物中它是高度保守的。使用分子分析，我们确定了介导ZFHX3 SUMOylation的酶。其中包括SUMO1激活酶亚基1（SAE1），一种E1激活酶；SUMO-缀合酶UBC9（UBC9），一种E2缀合酶；E3连接酶激活的STAT2（PIAS2）的蛋白抑制剂。多项分析确定，SUMO特异性肽酶1（SENP1）和SENP2都将SUF水解ZFHX3。Lys-2806的SUMOylation通过干扰ZFHX3的泛素化和蛋白酶体降解来增强其稳定性。在功能上，Lys-2806 SUMOylation使ZFHX3介导的MDA-MB-231乳腺癌细胞系细胞增殖和异种移植瘤生长。这些发现揭示了参与其中的酶及其功能后果