The Role of MYST histone acetyltransferases in genome stability

动态的蛋白质乙酰化对于正常的细胞生理是必不可少的，涉及的酶的缺陷有 与多种人类疾病有关。组蛋白乙酰转移酶的Myst家族高度 从酵母到人类都是保守的，它们是大型多蛋白复合体的催化亚单位，其 结构组成也是保守的。Myst乙酰转移酶的异常重排或调节 与人类癌症有关。然而，我们对它们的关键蛋白质底物知之甚少 它们在较大的蛋白质复合体中扮演的角色，或控制其功能的遗传调控途径。 最近的进展使解决这些问题变得可行和令人兴奋。我们正在研究分子 Myst家族的两个标志性成员的遗传学：发芽酵母的Esa1酶和Hbo1 人类的酵素。ESA1编码芽殖酵母中唯一必需的组蛋白乙酰转移酶。它是 两个多蛋白复合体的催化亚基，NuA4和PicNuA4。我们最近有了一个令人惊讶的发现 这种催化作用并不像之前认为的那样是ESA1的基本功能。相反，我们建议ESA1是一个 NuA4复合体的调节亚单位，使用其催化结构域作为生理信号的传感器。我们会 进行旨在识别ESA1检测到的启动信号的实验，并了解 NuA4的信号转导机制。我们将剖析esa1抑制子的分子遗传学。 突变，并检测ESA1突变后调控基因启动子的染色质变化 和抑制者。这些实验的结果将彻底改变我们思考问题的方式 ESA1和NuA4起作用。Hbo1是人类Myst家族的一种酶，是Hbo1的催化亚单位 包括ING和JADE肿瘤抑制因子家族成员的多蛋白质复合体。我们发现 Hbo1在DNA复制许可的复制前复合体的组装中具有因果作用。我们的 结果预测前RC蛋白可能是Hbo1乙酰化的直接底物。我们将进行实验 确定赖氨酸乙酰化的位点及其促进许可的分子机制。我们 最近还发现抑癌基因P53和Hbo1在物理和功能上相互作用。我们建议 这种相互作用是决定细胞分裂周期停滞和细胞凋亡的机制的一部分。 对生理压力的反应。我们将通过进行实验来验证这一假设，以确定一部小说 Hbo1蛋白底物参与该途径并检测其在促凋亡基因调控中的作用 抄写。这些实验将极大地扩展我们对Hbo1调节DNA功能的理解 复制和细胞增殖。

Dynamic protein acetylation is essential for normal cell physiology and defects in the enzymes involved are associated with a wide variety of human diseases. The MYST family of histone acetyltransferases are highly conserved, from yeast to man, and they serve as the catalytic subunits of large multi-protein complexes whose structural compositions are also conserved. Aberrant rearrangements or regulation of MYST acetyltransferases are associated with human cancers. However, we know relatively little about their critical protein substrates, the roles they play in the larger protein complexes, or the genetic regulatory pathways that control their function. Recent advances now make tackling these problems feasible and exciting. We are investigating the molecular genetics of two signature members of the MYST family: the Esa1 enzyme of budding yeast, and the Hbo1 enzyme of humans. ESA1 encodes the only essential histone acetyltransferase in budding yeast. It is the catalytic subunit of two multi-protein complexes, NuA4 and picNuA4. We recently made the surprising discovery that catalysis is not the essential function of Esa1, as previously thought. Instead, we propose that Esa1 is a regulatory subunit of NuA4 complexes that uses its catalytic domain as a sensor of physiological signals. We will carry out experiments designed to identify the initiating signals detected by Esa1, and to understand the mechanism of signal transduction through NuA4. We will dissect the molecular genetics of suppressors of esa1 mutations and examine the chromatin changes at promoters of regulated genes in response to esa1 mutations and suppressors. The results of these experiments are poised to completely change the way we think about Esa1 and NuA4 function. Hbo1 is a human MYST family enzyme that serves as the catalytic subunit of multi-protein complexes that include members of the Ing and Jade tumor suppressor families. We discovered that Hbo1 has a causal role in the assembly of the pre-replicative complex for DNA replication licensing. Our results predict that pre-RC proteins may be direct substrates for Hbo1 acetylation. We will carry out experiments to identify sites of lysine acetylation and the molecular mechanism through which they facilitate licensing. We also recently found that tumor suppressor p53 and Hbo1 interact physically and functionally. We propose that this interaction is part of the mechanism that decides between cell division cycle arrest and apoptosis in response to physiological stresses. We will test this hypothesis by carrying out experiments to identify a novel protein substrate of Hbo1 implicated in the pathway and examine its role in regulating pro-apoptotic gene transcription. These experiments will greatly expand our understanding of Hbo1 function in regulating DNA replication and cell proliferation.