Role of PPM1D and PPM1D mutations in hematopoiesis and response to stress

项目摘要/摘要 PPM1D编码丝氨酸/苏氨酸磷酸酶，该酶在广泛的 癌症。我们已经证明，反复的C-末端截断会损害蛋白酶体对PPM1D的降解， 导致蛋白质水平和活性增加，这在克隆性造血和髓系中很常见 接受化疗后的恶性肿瘤。然而，PPM1D在造血过程中所起的作用 在稳态和应激条件下，PPM1D的分子机制通过 C-末端仍不清楚。我们开发了两种新的小鼠模型来研究PPM1D，现在在AIM上提出 1使用这些模型研究PPM1D丢失和PPM1D激活如何通过C-末端截断影响 正常的造血和在放射线和炎症环境下的造血。我还表演了一场 遗传筛选发现，UBE3C是一种E3泛素连接酶，调节PPM1D和Protein in Aim的水平 2确定UBE3C如何通过与C末端的相互作用降解PPM1D，并定义更广泛的 泛素连接酶复合体调节PPM1D泛素化和蛋白酶体降解。总而言之，这 这项工作将有助于解释克隆造血和治疗相关髓系中PPM1D突变的流行情况 恶性肿瘤，定义了调节PPM1D水平的分子机制，并阐明了PPM1D作为一种 潜在的治疗靶点。申请者彼得·米勒博士是达纳-法伯癌症研究所的肿瘤学家 (DFCI)。他80%的时间用于翻译研究，20%用于临床实践，照顾患有 癌症。他勾勒出了一个五年的职业发展计划，以实现他成为独立人士的目标 翻译研究中的调查员。米勒博士组建了一个国际咨询委员会 公认的专家提供科学和职业指导。他已经与专业人士建立了合作关系 在造血、小鼠模型、泛素蛋白酶体系统、质谱学和应用生物统计学方面 在该领域提供实验建议和具体培训。米勒博士将在DFCI进行这项研究 并利用DFCI、哈佛和布罗德研究所卓越的研究和教学环境。 DFCI拥有一个杰出的研究社区，并有成功的长期记录 独立内科科学家的指导是完成这些实验的理想环境， 实现了米勒博士长期的职业目标，即成为一名独立的内科科学家。

Project Summary/Abstract PPM1D encodes for a serine/threonine phosphatase that is recurrently amplified and mutated in a wide range of cancers. We have shown that recurrent C-terminal truncations impair PPM1D degradation by the proteasome, leading to increased protein levels and activity, and are common in clonal hematopoiesis and myeloid malignancies after the receipt of chemotherapy. However, the role that PPM1D plays in hematopoiesis during steady state and under conditions of stress, and the molecular mechanism by with PPM1D is degraded via the C-terminus remains unclear. We developed two novel mouse models to study PPM1D and now propose in Aim 1 to use these models to investigate how PPM1D loss and PPM1D activation via C-terminal truncation affect normal hematopoiesis and hematopoiesis in the setting of radiation and inflammation. I have also performed a genetic screen and found that UBE3C, an E3 ubiquitin ligase, regulates the levels of PPM1D and propose in Aim 2 to determine how UBE3C degrades PPM1D via interactions with the C-terminus and to define the broader ubiquitin ligase complex regulating PPM1D ubiquitination and degradation by the proteasome. Collectively, this work will help explain the prevalence of PPM1D mutations in clonal hematopoiesis and therapy-related myeloid malignancies, define the molecular machinery that regulates PPM1D levels, and shed light on PPM1D as a potential therapeutic target. The applicant, Dr. Peter Miller, is an oncologist at the Dana-Farber Cancer Institute (DFCI). He spends 80% of his time in translational research and 20% in clinical practice caring for patients with cancer. He has outlined a five-year career development plan to meet his goal of becoming an independent investigator in translational research. Dr. Miller has assembled an Advisory Committee of internationally recognized experts to provide scientific and career mentorship. He has established collaborations with expertise in hematopoiesis, mouse models, the ubiquitin proteasome system, mass spectrometry, and applied biostatistics to provide experimental advice and specific training in the field. Dr. Miller will conduct this research at the DFCI and leverage the exceptional research and teaching environment at the DFCI, Harvard, and the Broad Institute. The DFCI, which harbors an outstanding research community and has a long track record for successful mentorship of independent physician scientists, is an ideal environment for completion of these experiments and the realization of Dr. Miller’s long-term career goal of being an independent physician-scientist.