Molecular functions of the shelterin component ACD/TPP1 in somatic stem cells and tissue homeostasis

成体干细胞和组织稳态中庇护蛋白成分 ACD/TPP1 的分子功能

• 批准号: 9116736
• 负责人: Catherine ELIZABETH Keegan
• 金额: $ 46.36万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9116736
• 关键词: Acute; Affect; Aging; Aging-Related Process; Alleles; Amino Acids; Binding; Binding Proteins; Biological Assay; Biology; Bone Marrow; CRISPR/Cas technology; Cell Line; Cell physiology; Cells; Chromosomes; Complex; DNA; DNA Damage; DNA biosynthesis; Data; Defect; Development; Disease; Dyskeratosis Congenita; Engineering; Enzymes; Failure; Functional disorder; Gene Components; Genes; Genetic Materials; Genomic Instability; Goals; Health; Hematopoiesis; Hematopoietic; Hematopoietic stem cells; Homeostasis; Human; In Vitro; Individual; Life; Longevity; Maintenance; Maps; Membrane Proteins; Missense Mutation; Modeling; Molecular; Mus; Mutation; Organ; Organism; Pancytopenia; Patients; Physiology; Play; Point Mutation; Population; Premature aging syndrome; Proteins; Recruitment Activity; Regulation; Role; Stem cells; Stress; Surface; Syndrome; TINF2 gene; Technology; Telomerase; Telomere Maintenance; Testing; Therapeutic; Tissues; Translating; Variant; Work; base; early onset; genetic variant; genome editing; human disease; in vivo; in vivo Model; insight; interdisciplinary approach; mouse genome; mutant; prevent; proband; repaired; research study; response; senescence; stem cell population; telomere

 DESCRIPTION (provided by applicant): The six-protein shelterin complex cooperates with telomerase to maintain the integrity of chromosomal ends. As part of shelterin, the protein ACD/TPP1 protects telomeric ends from the DNA damage response machinery. Additionally, ACD/TPP1 is uniquely involved in recruiting telomerase to telomeres through a dedicated protein surface known as the TEL patch. Both end-protection and end-elongation are important for the maintenance and function of somatic stem cells in aging tissues. We showed that ACD/TPP1 has essential context- specific functions in hematopoietic stem cells and in other tissues. Recent work identified candidate ACD/TPP1 mutations in patients with Dyskeratosis congenita, a human disorder characterized by impaired somatic stem cell function in the bone marrow and other organs, with features of premature aging. This is the first identification of ACD/TPP1 mutations in human disease. Our preliminary data show that these mutations can disrupt telomerase recruitment and telomere homeostasis in cell lines. However, how telomere maintenance defects in cells due to ACD/TPP1 mutations translate to dysfunction of specific stem cell compartments in vivo and how they contribute to tissue aging and disease is not understood. We hypothesize that ACD/TPP1 mutations can play a causative role in Dyskeratosis congenita and related somatic stem cell disorders. Furthermore, we postulate that point mutations affecting the interface of ACD/TPP1 with its protein partners can reveal unique functions of the shelterin complex when modeled in mammalian tissues. To explore this hypothesis in detail, we will study candidate mutations and other variants affecting binding of ACD/TPP1 with telomerase or with its shelterin partner TIN2, using modern genome-editing technology to assess their in vivo effects in the entire organism. Our Specific Aims are to: 1) Evaluate the impact of candidate human ACD/TPP1 TEL patch mutations on hematopoietic stem cells and bone marrow homeostasis; 2) Determine the structural requirements for the interaction of ACD/TPP1 with TIN2 and the functional consequences of defective TIN2- ACD/TPP1 binding; 3) Investigate how tissue homeostasis and longevity are affected by candidate ACD/TPP1 pathogenic variants that disrupt interaction with key protein partners. Our multidisciplinary approach will identify distinct functional surfaces of ACD/TPP1 and determine their impact on stem cells, tissue homeostasis and aging. We anticipate that we will uncover how mutational dysregulation of ACD/TPP1 and the shelterin/telomerase complex can ultimately result in human disease.

 描述（由申请人提供）： 六蛋白庇护蛋白复合物与端粒酶合作维持染色体末端的完整性。作为庇护蛋白的一部分，蛋白质 ACD/TPP1 可以保护端粒末端免受 DNA 损伤反应机制的影响。通过称为 TEL 补丁的专用蛋白质表面，独特地参与将端粒酶募集到端粒中，末端保护和末端延伸都很重要。我们发现 ACD/TPP1 在造血干细胞和其他组织中具有重要的特定功能，最近的工作在人类先天性角化不良患者中发现了候选 ACD/TPP1 突变。其特征是骨髓和其他器官中的成体干细胞功能受损，并具有过早衰老的特征。这是人类疾病中首次鉴定出 ACD/TPP1 突变。我们的初步数据表明，这些突变可以破坏人类疾病。然而，ACD/TPP1 突变导致的细胞端粒维持缺陷如何转化为体内特定干细胞区室的功能障碍以及它们如何导致衰老和疾病组织尚不清楚。 /TPP1 突变可能在先天性角化不良和相关的成体干细胞疾病中发挥致病作用。此外，我们假设点突变影响 ACD/TPP1 与其蛋白的界面。在哺乳动物组织中建模时，合作伙伴可以揭示庇护蛋白复合物的独特功能。为了详细探索这一假设，我们将使用现代基因组编辑研究影响 ACD/TPP1 与端粒酶或其庇护蛋白伴侣 TIN2 结合的候选突变和其他变异。我们的具体目标是： 1) 评估候选人类 ACD/TPP1 TEL 补丁突变对造血干细胞和骨髓的影响。稳态；2) 确定 ACD/TPP1 与 TIN2 相互作用的结构要求以及 TIN2-ACD/TPP1 结合缺陷的功能后果；3) 研究破坏相互作用的候选 ACD/TPP1 致病变异如何影响组织稳态和寿命。我们的多学科方法将识别 ACD/TPP1 的独特功能表面，并确定它们对干细胞、组织稳态和衰老的影响。将揭示 ACD/TPP1 和庇护蛋白/端粒酶复合物的突变失调如何最终导致人类疾病。