Regulatory functions of the SUMO system in ribosome biogenesis and mitosis

SUMO 系统在核糖体生物合成和有丝分裂中的调节功能

• 批准号: 72128078
• 负责人: Professor Dr. Stefan Müller
• 金额: --
• 依托单位: Institut für Biochemie II
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/72128078?language=en
• 关键词: Regulatory; functions; SUMO; system; ribosome

The reversible post-translational modification of proteins by the ubiquitin-like SUMO modifier controls key cellular pathways. The alteration of a given substrate between modification and demodification can determine its spatial distribution or regulate the assembly or disassembly of protein complexes. SUMO-specific proteases of the SENP family accurately govern the state of modification by catalyzing the deconjugation of SUMO from target proteins. The further characterization of SENP family members is thus of major importance to gain novel insights into SUMO function. In this proposal we concentrate on the role of SENP3 in ribosome biogenesis (Part I) and the involvement of SENP3 and SENP6 in the control of mitotic processes (Part II).Our previous work uncovered a regulatory role of SENP3 in the nucleolar steps of ribosome biogenesis and showed that this function is linked to nucleophosmin (NPM1). In the first funding period we now identified and characterized a novel SENP3-associated complex comprised of PELP1, TEX10 and WDR18 and demonstrate that this complex is involved in maturation and nucleolar release of the large ribosomal subunit. We found that PELP1 is dynamically modified by SUMO2/3 in a SENP3-controlled process and we provide evidence that the SUMO system determines the nucleolar partitioning of PELP1. We propose a model where the balanced sumoylation-desumoylation controls the dynamic association of the PELP1-WDR18-TEX10 complex with 60S pre-ribosomal particles and hypothesize that loss of SENP3 induces the premature release of the complex from these structures.In part I of the project we will challenge this hypothesis and ask the following questions:1. How does sumoylation affect composition and dynamics of ribosomal particles?2. How are AAA-ATPases involved in SUMO-dependent remodelling of pre-ribosomes?3. How do c-myc and p14ARF control SENP3 and the nucleolar SUMO system?Previous work by our group and others has also determined an important role of the mammalian SUMO system in the control of mitotic functions. Depletion of SENP3 by siRNA prevents mitotic arrest of cells upon addition of spindle poisons indicating that SENP3 functions in the spindle assembly checkpoint (SAC). We could define Borealin, a component of the chromosomal passenger complex (CPC), as a first mitotic substrate of SENP3. In the first funding period we gained new insight into mitotic regulation of SENP3 and revealed an interconnection of SENP3 with the mitotic kinase Plk1. We additionally observed that depletion of SENP6, which exerts specificity for SUMO2/3-chains, also affects SAC activity. Moreover, we identified the SAC component MAD1 as a SENP6-sensitive target of SUMO2/3.In part II the new funding period we will now concentrate on the following questions:1. How are SENP3 and PLK1 functionally connected?2. Is Mad1 a substrate for the SUMO-dependent degradation pathway?3. What is the role of SUMO2/3-chains in the control of MAD1 activity and recognitionby SENP6?

泛素样的Sumo修饰剂对蛋白质的可逆后翻译后修饰控制关键细胞途径。给定底物在修饰和解换之间的改变可以确定其空间分布或调节蛋白质复合物的组装或拆卸。 SENP家族的Sumo特异性蛋白酶通过催化靶蛋白的Sumo的解偶来准确控制修饰状态。因此，SENP家族成员的进一步表征对于获得对相扑功能的新见解至关重要。在此提案中，我们集中于SENP3在核糖体生物发生中的作用（第I部分）以及Senp3和Senp6在控制有丝分裂过程中的参与（第二部分）。您以前的工作发现了Senp3在核糖体生物发生核酸核步骤中的调节作用，并表明该功能与核粒细胞（Nppmin（NppM1）相关。在第一个资金期间，我们现在确定并表征了由PELP1，TEX10和WDR18组成的新型SENP3相关的复合物，并证明该复合物与大核糖体亚基的成熟和核仁释放有关。我们发现，在SENP3控制的过程中，PELP1通过SUMO2/3动态修饰，我们提供了SUMO系统确定PELP1的核仁分配的证据。我们提出了一个模型，在其中平衡的sumoylation-desumoylation控制着PELP1-WDR18-TEX10复合物与60s的60s前核糖体颗粒的动态关联，并假设SENP3的损失会导致该综合体的早期释放，从这些结构中释放了这些结构。 Sumoylation如何影响核糖体颗粒的组成和动力学？2。 aaA-atpass如何参与前丝体的相关重塑？3。 C-MYC和P14ARF控制SENP3和核仁Sumo系统如何？我们小组和其他人的先前工作也确定了哺乳动物Sumo系统在控制有丝分裂功能中的重要作用。 siRNA对SENP3的耗竭可阻止添加纺锤体毒物后细胞的有丝分裂停滞，表明SENP3在纺锤体组装检查点（SAC）中的功能。我们可以将Borealin（染色体乘客复合物（CPC）的组成部分）定义为SENP3的第一个有丝分裂底物。在第一个资金期间，我们对SENP3有丝分裂调节进行了新的了解，并揭示了SENP3与有丝分裂激酶PLK1的互连。我们还观察到，对SUMO2/3链具有特异性的SENP6的耗竭也会影响SAC活性。此外，我们将SAC组件MAD1确定为SENP6敏感的SUMO2/3的目标。在第二部分中，我们现在将集中于以下问题：1。 SENP3和PLK1如何连接？2。 MAD1是相关性降解途径的底物吗？3。 SUMO2/3链在控制MAD1活动和识别SENP6中的作用是什么？