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

项目摘要 PPM 1D编码丝氨酸/苏氨酸磷酸酶，其在广泛的细胞内反复扩增和突变。 癌的我们已经表明，经常性的C-末端截短损害了蛋白酶体对PPM 1D的降解， 导致蛋白质水平和活性增加，并且在克隆造血和髓系造血中是常见的。 接受化疗后的恶性肿瘤。然而，PPM1D在造血过程中的作用， 稳定状态和应力条件下，与PPM 1D的分子机制是通过降解 C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中提出 1使用这些模型研究PPM 1D丢失和PPM 1D通过C-末端截短激活如何影响 正常造血和在辐射和炎症情况下的造血。我还表演了 遗传筛选发现E3遍在蛋白连接酶UBE 3C调节PPM 1D的水平，并在Aim中提出 2，以确定UBE3C如何通过与C-末端的相互作用降解PPM 1D，并定义更广泛的 泛素连接酶复合物通过蛋白酶体调节PPM1D泛素化和降解。总的来说，这 这项工作将有助于解释PPM1D突变在克隆性造血和治疗相关的髓系白血病中的流行。 恶性肿瘤，定义了调节PPM1D水平的分子机制，并阐明了PPM1D作为 潜在的治疗靶点。申请人彼得米勒博士是丹娜-法伯癌症研究所的肿瘤学家 （DFCI）。他将80%的时间用于转化研究，20%的时间用于临床实践， 癌他已经制定了一个五年职业发展计划，以实现他成为一名独立的 翻译研究的研究者。米勒博士召集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，和应用生物统计学 提供实验咨询和实地具体培训。米勒博士将在DFCI进行这项研究 并充分利用DFCI、哈佛和布罗德研究所的卓越研究和教学环境。 DFCI拥有一个杰出的研究社区，并有着长期的成功记录。 独立医生科学家的指导，是完成这些实验的理想环境， 实现了米勒博士的长期职业目标，即成为一名独立的医学科学家。

Project Summary 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.