Regulation and Function of Phosphoinositide Lipid Signalling

磷酸肌醇脂质信号传导的调节和功能

• 批准号: RGPIN-2015-06489
• 负责人: Botelho, Roberto
• 金额: $ 2.48万
• 依托单位: Ryerson University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=685345
• 关键词: Regulation; Function; Phosphoinositide; Lipid; Signalling

Membrane-bound organelles are the "organs" of cells. There are many organelle types, each with distinct biophysical, biochemical and functional properties. For example, the endoplasmic reticulum is a labyrinth of membrane tubules where protein synthesis occurs, whereas lysosomes are small, round organelles full of digestive enzymes. How organelles form or change is a central question in cell biology. ******The phosphoinositide (PIP) lipids are architects of organelle identity. There are seven PIP species that are differentially distributed among organelles. Since each PIP species binds and recruits a unique set of proteins, then this decorates the host organelle with a unique set of molecular properties. In order to understand how PIPs help to determine organelle identity, cell biologists need to understand A) how the enzymes that synthesize and degrade PIPs are targeted and regulated and B) how PIPs and their effector proteins work. ******Here, I propose to study a specific PIP, phosphatidylinositol-3,5-bisphosphate [PI(3,5)P2], which controls the morphology and membrane traffic of organelles in the endocytic pathway. This pathway is responsible for sorting and trafficking proteins to various destinations including the cell surface or for degradation in lysosomes. It also interfaces with the phagocytic pathway, which immune cells use to destroy pathogens. With NSERC support:******i) We will study the role of PI(3,5)P2 and its effectors in macrophages and neutrophils. These immune cells hunt and engulf pathogens into phagosomes to digest and kill them. We have previously showed that phagosomes require PI(3,5)P2 to become degradative in macrophages. The new research will seek to understand how PI(3,5)P2 is important for phagosome maturation and explore its role in neutrophils, the first responders to an infection. ******ii) We will perform unprecedented studies to understand how PI(3,5)p2 controls lysosome size by following the dynamics, kinetics and mechanisms by which PI(3,5)P2 depletion causes massive lysosome swelling. This dramatic change to lysosomes remains poorly uncharacterized. ******iii) We will study the origin and functions of two different pools of PI(3)P in cells. PI(3)P is the precursor for PI(3,5)P2, but it is unclear when and where this conversion occurs. Using cutting-edge research and genetic engineering, we will aim to better understand how individual pools of PI(3)P function, which will then inform us about the transition of PI(3)P to PI(3,5)P2.******Overall, my research will answer questions in cell biology related to PIP regulation and function. These answers may then have implications for organismal well-being since PI(3,5)P2 dysfunction causes neurodegeneration and may disrupt the immune response. Our findings may provide the Canadian biotechnology and pharmaceutical industries with novel strategies to treat conditions caused by PIP malfunction that afflicts Canadians.**

膜结合的细胞器是细胞的“器官”。 有许多细胞器类型，每一种都具有不同的生物物理，生物化学和功能特性。 例如，内质网是一个膜小管的迷宫，蛋白质合成发生在这里，而溶酶体是小而圆的细胞器，充满了消化酶。 细胞器如何形成或变化是细胞生物学的核心问题。** 磷脂酰肌醇（PIP）脂质是细胞器身份的建筑师。 有七种PIP物种在细胞器中有差异分布。 由于每个PIP种类都结合并招募了一组独特的蛋白质，因此这会用一组独特的分子特性装饰宿主细胞器。 为了了解PIP如何帮助确定细胞器的身份，细胞生物学家需要了解A）合成和降解PIP的酶如何被靶向和调节，以及B）PIP及其效应蛋白如何工作。** 在这里，我建议研究一种特定的PIP，磷脂酰肌醇-3，5-二磷酸[PI（3，5）P2]，它控制着内吞途径中细胞器的形态和膜交通。该途径负责将蛋白质分选和运输到包括细胞表面在内的各种目的地或在溶酶体中降解。 它还与吞噬细胞途径相互作用，免疫细胞利用吞噬细胞途径来破坏病原体。 在NSERC的支持下：**i）我们将研究PI（3，5）P2及其效应物在巨噬细胞和中性粒细胞中的作用。 这些免疫细胞将病原体捕获并吞噬到吞噬体中，以消化并杀死它们。 我们以前已经表明，吞噬体需要PI（3，5）P2成为降解巨噬细胞。 这项新的研究将试图了解PI（3，5）P2对吞噬体成熟的重要性，并探索其在中性粒细胞中的作用，中性粒细胞是感染的第一反应者。 **ii）我们将进行前所未有的研究，以了解PI（3，5）P2如何通过遵循PI（3，5）P2消耗引起大量溶酶体肿胀的动力学、动力学和机制来控制溶酶体大小。 这种对溶酶体的巨大变化仍然没有得到很好的表征。**iii）我们将研究细胞中两种不同PI（3）P库的起源和功能。 PI（3）P是PI（3，5）P2的前体，但尚不清楚这种转化何时何地发生。 利用尖端研究和基因工程，我们的目标是更好地了解PI（3）P的单个池如何发挥作用，然后告诉我们PI（3）P向PI（3，5）P2的过渡。总的来说，我的研究将回答与PIP调节和功能相关的细胞生物学问题。 这些答案可能对生物体的健康有影响，因为PI（3，5）P2功能障碍会导致神经变性，并可能破坏免疫反应。我们的研究结果可能为加拿大生物技术和制药行业提供新的策略，以治疗困扰加拿大人的PIP故障引起的疾病。