Integrating stress MAP kinase signaling with DNA replication origin licensing

将应激 MAP 激酶信号传导与 DNA 复制起点许可相结合

• 批准号: 8584099
• 负责人: Jeanette Gowen Cook
• 金额: $ 28.57万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8584099
• 关键词: Affect; Anaphase; Biological Markers; Cell Cycle; Cell Cycle Arrest; Cell Cycle Regulation; Cell Death; Cell Proliferation; Cells; Cellular Stress; Chromosome Segregation; Chromosomes; Chronic; Competence; Complex; Coupled; Cues; Cyclin-Dependent Kinases; DNA; DNA Damage; DNA biosynthesis; DNA replication origin; Data; Disease; Ensure; Environment; Enzymes; Event; Failure; Foundations; G1 Arrest; G1 Phase; G2 Phase; Genetic; Genome; Genome Stability; Genomic Instability; Goals; Homeostasis; Human; Inflammation; Inflammatory; Investigation; Kinetochores; Lead; Learning; Licensing; MAPK14 gene; MAPK8 gene; Malignant Neoplasms; Mediating; Microtubules; Mitogen-Activated Protein Kinases; Mitosis; Mitotic; Modeling; Molecular; Mutagens; Mutation; Normal Cell; Pathology; Phospho-Specific Antibodies; Phosphorylation; Phosphorylation Site; Physiological; Play; Poison; Positioning Attribute; Process; Proliferating; Proteins; Regulation; Relative (related person); Research; Role; S Phase; Signal Pathway; Signal Transduction; Source; Stress; Structure; Testing; Therapeutic; Tissues; acute stress; base; chromosome replication; extracellular; human disease; improved; inhibitor/antagonist; insight; mitogen-activated protein kinase p38; mutant; novel; prevent; public health relevance; segregation; tool; tumorigenesis

DESCRIPTION (provided by applicant): Timely, complete, and precise DNA replication followed by accurate chromosome segregation is critical for controlling cell proliferation and genome stability. Improperly controlled replication contributes to cell death, tissue degeneration, and cancer. For these reasons we seek to define molecular mechanisms that govern DNA replication competence and coordination with cell cycle control. Origin licensing is the earliest step in DNA replication, and failure to coordinate origin licensing with the cell division cycle leads to under-replicated or re- replicated chromosomal regions which are sources of cell death and genome instability. Our long-term goal is to determine precisely how origin licensing proteins are regulated by intracellular cell cycle cues and by extracellular signaling pathways. Current paradigms rely on a combination of direct and indirect control of origin licensing by the cyclin dependent kinases (CDKs). Based on documented roles in cell proliferation, we reasoned that a signaling pathway mediated by the stress-activated MAP kinases, p38 and JNK, could have an equally important impact on origin licensing. Recent studies have shown that stress MAP kinases also play key roles even in unperturbed cell cycles, but the interfaces between MAP kinases and fundamental events in the cell cycle are not fully known. Our investigations revealed that these stress MAP kinases directly inhibit origin licensing, and they inactivate the licensing protein Cdt1 by direct phosphorylation. Importantly, others have shown that stress MAP kinases also function in unperturbed cell cycles to govern cellular quiescence, G2 phase, and mitosis - normal circumstances in which origin licensing must be inhibited. Determining the mechanisms of origin licensing inhibition by MAP kinases is one focus of this proposal. In addition, we have uncovered a novel chromosome segregation function for Cdt1 independent of its replication role, and MAP kinase-mediated phosphorylation affects this Cdt1 mitotic function. We hypothesize that stress MAP kinases directly govern fundamental steps in chromosome replication competence and mitotic segregation. Our objective is to determine the mechanisms and physiological roles of MAP kinase regulation of origin licensing proteins. Our prior studies and expertise coupled with this objective inspire the following Aims: (1) Determine the role of stress MAP kinases in blocking origin licensing and Cdt1 function in proliferating cells, (2) Determine the role of stress MAP kinases in establishing the unlicensed state of quiescent cells during cell cycle exit, (3) Determine the role of MAP kinase-mediated Cdt1 phosphorylation in regulating Cdt1's function in chromosome segregation. Elucidating the mechanisms by which p38 and JNK MAP kinases impact these key cell cycle transitions will lead to new, integrated models of cell cycle control. These models can then be used to understand the physiological consequences of activating or inhibiting the stress MAP kinases during normal cell proliferation, differentiation, and organismal homeostasis and in pathological settings such as chronic inflammation and cancer.

描述（由申请人提供）：及时、完整和精确的 DNA 复制以及准确的染色体分离对于控制细胞增殖和基因组稳定性至关重要。复制控制不当会导致细胞死亡、组织退化、 和癌症。出于这些原因，我们寻求定义控制 DNA 复制能力以及与细胞周期控制协调的分子机制。起源许可是 DNA 复制的最早步骤，如果起源许可与细胞分裂周期不协调，就会导致染色体区域复制不足或重复复制，而这些区域是细胞死亡和基因组不稳定的根源。我们的长期目标是精确确定细胞内细胞周期线索和细胞外信号通路如何调节起源许可蛋白。当前的范例依赖于细胞周期蛋白依赖性激酶（CDK）对来源许可的直接和间接控制的组合。根据记录在细胞增殖中的作用，我们推断由应激激活的 MAP 激酶、p38 和 JNK 介导的信号通路可能对原产地许可产生同样重要的影响。最近的研究表明，即使在未受干扰的细胞周期中，应激 MAP 激酶也发挥着关键作用，但 MAP 激酶与细胞周期中基本事件之间的界面尚不完全清楚。我们的研究表明，这些应激 MAP 激酶直接抑制起源许可，并且它们通过直接磷酸化使许可蛋白 Cdt1 失活。重要的是，其他人已经表明，应激 MAP 激酶也在未受干扰的细胞周期中发挥作用，以控制细胞静止、G2 期和有丝分裂——必须抑制起源许可的正常情况。确定 MAP 激酶的起源许可抑制机制是该提案的重点之一。此外，我们还发现了 Cdt1 的一种新的染色体分离功能，与其复制作用无关，并且 MAP 激酶介导的磷酸化会影响 Cdt1 有丝分裂功能。我们假设应激 MAP 激酶直接控制染色体复制能力和有丝分裂分离的基本步骤。我们的目标是确定 MAP 激酶调节起源许可蛋白的机制和生理作用。我们之前的研究和专业知识与这一目标相结合，激发了以下目标：(1) 确定应激 MAP 激酶在阻断增殖细胞中的起源许可和 Cdt1 功能中的作用，(2) 确定应激 MAP 激酶在细胞周期退出期间建立静止细胞的未许可状态中的作用，(3) 确定 MAP 激酶介导的 Cdt1 磷酸化在调节 Cdt1 功能中的作用 染色体分离。阐明 p38 和 JNK MAP 激酶影响这些关键细胞周期转变的机制将产生新的细胞周期控制综合模型。然后，这些模型可用于了解在正常细胞增殖、分化和有机体稳态以及慢性炎症和癌症等病理环境中激活或抑制应激 MAP 激酶的生理后果。