Bistability and trigger waves in cell signaling

细胞信号传导中的双稳态和触发波

• 批准号: 10576420
• 负责人: JAMES E. FERRELL
• 金额: $ 68.59万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10576420
• 关键词: Action Potentials; Apoptosis; Apoptotic; Axon; Biological Pacemakers; Biological Process; Biology; Calcium Oscillations; Cell Cycle Regulation; Cells; Centrosome; Cilia; Cytoplasm; Dendrites; Diffusion; Enzymes; Evolution; Feedback; Fire - disasters; Infection; Innate Immune Response; Innate Immune System; Interferons; Internet; Interphase; Microfluidic Microchips; Mitosis; Mitotic; Modeling; Natural regeneration; Organism; Process; Protein Phosphatase 2A Regulatory Subunit PR53; Proteins; Signal Transduction; Structure; System; Temperature; Testing; Tissues; Tube; Variant; Viral; Work; Xenopus; Xenopus laevis; base; egg; experimental study; fascinate; response; self organization; theories

PROJECT SUMMARY/ABSTRACT We have been studying cell cycle regulation in Xenopus laevis eggs and extracts, carrying out a combination of quantitative experiments and modeling to understand how this biological oscillator works and what features it shares with other regulatory systems. The oscillator circuit includes a positive feedback-based bistable trigger, which opens the possibility that Cdk1 activity might spread through cytoplasm by what are termed trigger waves: self-regenerating activity waves, where some active Cdk1 diffuses a small distance and brings about the activation of the inactive Cdk1 in that volume through the positive feedback, which then diffuses locally and repeats the process. Action potentials are trigger waves; so are calcium waves, as is the spread of a fire through a field or the spread of a joke on the internet. We recently showed that both mitosis and apoptosis spread through Xenopus cytoplasm via trigger waves. We plan to build upon this, and determine: · What mechanism underpins the ability of interphase Xenopus cytoplasm to self-organize into cell-like structures? This was an unexpected observation we made in the course of our apoptosis studies, and it is a fascinating phenomenon to try to understand. · Is the apoptotic control circuit a bistable system? Our discovery of apoptotic trigger waves suggests that it is, but others have argued that it may not be. We plan to settle the issue with direct experiments. · Saltatory vs. continuous mitotic waves. We plan to see whether Cdk1 activation propagates differently close to vs. far from the centrosome, where various pro-mitotic proteins concentrate. · Can bistability restrict signals to certain compartments? Theory tells us that a trigger wave may be blocked at the junction between a small tube and a big tube, like a dendrite/axon junction or the base of a primary cilium. We plan to carry out experiments with apoptotic trigger waves in microfluidics devices to test whether this does occur. · Do innate immune responses spread via trigger waves? The innate immune system includes positive feedback loops, such as interferon-induced interferon release. This could allow cellular defenses to spread ahead of an infection in a sheet of cells. We plan to test this possibility experimentally. · Is there a second mitotic switch? We have found that bistability persists when Cdk1 activity is forced to be graded. Our working hypothesis is that double-negative feedback loops centered on PP2A-B55 are responsible for this bistability. We are testing this hypothesis with hysteresis experiments in extracts. · How to proteins that work together stay coordinated as temperature changes, especially in cold-blood organisms? Do enzymes that work together have similar activation energies and Q10 values? And/or has evolution selected particular circuits that tolerate high degrees of parameter variation?

项目摘要/摘要 我们一直在研究Xenopus laevis卵和提取物中的细胞周期调节，进行组合 定量实验和建模，以了解该生物学振荡器的工作原理以及什么特征 它与其他监管系统共享。振荡器电路包括基于反馈的积极双向 触发器，这打开了CDK1活性可能通过细胞质扩散的可能性 触发波：自我再生活动波，其中一些活动的CDK1扩散了很小的距离并带来 关于通过正反馈在该体积中激活无活性CDK1的激活，然后扩散 本地重复该过程。动作电位是触发波；钙波也是如此， 通过一个领域的大火或在互联网上开玩笑的传播。我们最近表明有丝分裂和 凋亡通过触发波通过爪蟾细胞质扩散。我们计划以此为基础，并确定： 哪种机制基于相间Xenopus细胞质自我组织成细胞样的能力。 结构？这是我们在凋亡研究过程中做出的意外观察，它 是一个引人入胜的现象。 ·凋亡控制电路是可靠的系统吗？我们发现凋亡触发波的发现表明 那是，但其他人认为可能不是。我们计划通过直接实验解决问题。 盐和连续有丝分裂波。我们计划查看CDK1激活的传播是否不同 接近与中心体的远距离，各种促丝质蛋白浓缩。 ·双稳定性可以将信号限制在某些隔间中吗？理论告诉我们，触发波可能是 在小管和大管之间的连接处被阻塞，例如树突/轴突连接处或底部 原发性纤毛。我们计划在微流体设备中使用凋亡触发波进行实验 测试是否确实发生这种情况。 ·先天免疫调查会通过触发波传播吗？先天免疫调查包括肯定 反馈回路，例如干扰素诱导的干扰素释放。这可以使蜂窝防御能够 在一片细胞中的感染前传播。我们计划通过实验测试这种可能性。 ·是否有第二个有丝分裂开关？我们发现，当CDK1活动被迫进行 分级。我们的工作假设是，以PP2A-B55为中心的双负反馈回路是 负责这种双重性。我们正在通过提取物中的滞后实验来检验这一假设。 ·如何一起工作的蛋白质随着温度的变化而保持协调，尤其是在冷血中 生物？一起工作的酶是否具有相似的激活能和Q10值？和/或 进化是否选择了耐受参数变化高度的特定电路？