Mechanisms and Architecture of Endo-lysosomal Ca2+ Signalling

内溶酶体 Ca2 信号传导的机制和结构

• 批准号: BB/T01640X/1
• 负责人: A Galione
• 金额: $ 103.31万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FT01640X%2F1
• 关键词: Mechanisms; Architecture; Endo; lysosomal; Ca2+

Ca2+ serves an essential signal within every cell. Ca2+ levels inside cells are very low, partly because it is sequestered inside Ca2+-storing compartments. In response to cell stimuli, Ca2+ is released from these stores by opening resident ion channels to activate detector proteins ('decoders') and change cell processes. The increase in intracellular Ca2+ is a universal signal in virtually all cells types e.g. for fertilization, muscle contraction, nerve impulses, gene expression.The largest and best understood Ca2+ store is the endoplasmic reticulum (ER) which contains millimolar Ca2+. ER Ca2+ channels, IP3 receptors, are activated by a second messenger, IP3, which is synthesised in response to cell stimuli (e.g. hormones, neurotransmitters, antibodies, cell contact). IP3 synthesis, IP3R activation and Ca2+ release occur rapidly upon stimulation. However, the ER is not the only Ca2+ store and we discovered that small acidic vesicles (including endosomes and lysosomes) are important Ca2+ stores, but with their own unique second messenger (NAADP) and Ca2+ channels (TPCs), analogous to IP3/IP3Rs. This axis forms our focus.Although they are better known as cellular waste-bins, endo-lysosomes are emerging as dynamic signalling hubs, integrating and delivering signals in response to the environment. A major endo-lysosomal signal is Ca2+. Many stimuli couple to endo-lysosomal Ca2+ release as a transduction pathway: depending on the stimulus, cells synthesise the messenger, nicotinic acid adenine dinucleotide phosphate, NAADP, which opens TPCs (two-pore channels) expressed on endo-lysosomes. These are Ca2+-permeable and elevate cytosolic Ca2+. However, each vesicle is small so the limited amount of Ca2+ that is released generates local Ca2+ 'nanodomains' (a locally high concentration, restricted in space).Why does the cell contain different Ca2+ stores? The answer is that Ca2+ does not increase uniformly in the cytosol but rather is delivered discretely where it is needed. Different stores therefore deliver Ca2+ to different targets and different downstream physiology. We find endo-lysosomes 'pair-up' with their own unique detectors via highly localized and privileged conversations, for which the ER Ca2+ store cannot substitute. Therefore, each cell stimulus selects the appropriate Ca2+ sources for its downstream physiology.However, it is unclear how these essential endo-lysosomal Ca2+ signals are generated and decoded which therefore forms our focus. The NAADP/TPC axis is poorly defined in terms of targets. A further complexity is that endo-lysosomes are small, heterogeneous, motile and exquisitely positioned, interacting physically/functionally with other organelles in specialized junctions (e.g. with ER, mitochondria).Given the multiplicity of inputs/outputs, our aim is to understand how endo-lysosomes establish and regulate these 'private' local Ca2+ conversations with targets (proteins, organelles), thereby solving the Ca2+-specificity conundrum. Clearly, targets must closely associate with endo-lysosomes in order to detect the local 'Ca2+ plume' that emanates from TPCs. We aim to understand how targets are brought to endo-lysosomes or, conversely, how endo-lysosomes are dynamically brought to targets. We will identify how, when and where targets and decoders associate with TPCs. The placement and motility of endo-lysosomes is crucial for the physiology and we also will test whether there is a specialist sub-class of endo-lysosomes for different Ca2+ signalling roles.Potential Benefits & Applications. Standing at the crossroads of multiple processes, defining endo-lysosomal Ca2+ signals will:(a) illuminate basic science (Ca2+ signals, signal compartmentation, endo-lysosomal biology, organelle/membrane dynamics, Ca2+-decoding);(b) provide new tools to the broader cell biology community (reporters, pharmacology);(c) strengthen the case for organelle ion channels as new drug targets.

Ca 2+是每个细胞内的重要信号。细胞内的Ca 2+水平非常低，部分原因是它被隔离在Ca 2+储存室中。响应细胞刺激，Ca 2+通过打开驻留离子通道从这些存储器释放，以激活检测器蛋白（“解码器”）并改变细胞过程。细胞内Ca ~（2+）的增加是几乎所有细胞类型的普遍信号，例如受精、肌肉收缩、神经冲动、基因表达。ER Ca 2+通道，IP 3受体，被第二信使IP 3激活，IP 3是响应细胞刺激（例如激素，神经递质，抗体，细胞接触）而合成的。IP 3合成、IP 3R活化和Ca 2+释放在刺激后迅速发生。然而，ER不是唯一的Ca 2+储存，我们发现小的酸性囊泡（包括内体和溶酶体）是重要的Ca 2+储存，但具有自己独特的第二信使（NAADP）和Ca 2+通道（TPC），类似于IP 3/IP 3Rs。虽然内溶体通常被称为细胞废物箱，但它们正在成为动态信号中心，整合并传递信号以响应环境。主要的内-溶酶体信号是Ca 2+。许多刺激耦合到内-溶酶体Ca 2+释放作为转导途径：取决于刺激，细胞合成信使，烟酸腺嘌呤二核苷酸磷酸，NAADP，其打开内-溶酶体上表达的TPC（双孔通道）。这些是Ca 2+渗透性的，并升高细胞溶质Ca 2+。然而，每个囊泡都很小，所以释放的有限量的Ca 2+会产生局部的Ca 2+“纳米结构域”（局部高浓度，空间受限）。为什么细胞含有不同的Ca 2+储存？答案是Ca 2+在胞质溶胶中并不均匀增加，而是在需要的地方离散地传递。因此，不同的商店将Ca 2+输送到不同的目标和不同的下游生理。我们通过高度局部化和特权对话发现内溶体与其独特的检测器“配对”，这是ER Ca 2+储存无法替代的。因此，每种细胞刺激都为其下游生理选择合适的Ca ~（2+）来源，然而，这些必需的内-溶酶体Ca ~（2+）信号是如何产生和解码的，这是我们关注的焦点。NAADP/TPC轴在目标方面定义不清。更复杂的是，内溶体是小的、异质的、能动的和精确定位的，在专门的连接处与其他细胞器物理/功能相互作用。考虑到输入/输出的多样性，我们的目标是了解内溶酶体如何建立和调节这些“私人”局部Ca 2+与靶点的对话。（蛋白质，细胞器），从而解决了Ca 2+特异性难题。显然，靶标必须与内溶体紧密结合，以检测从TPC发出的局部“Ca 2+羽流”。我们的目标是了解目标是如何被带到内溶体，或者相反，内溶体是如何动态地被带到目标。我们将确定目标和解码器如何、何时以及在何处与TPC相关联。内溶体的位置和运动对于生理学是至关重要的，我们还将测试是否有一个专门的内溶体亚类用于不同的Ca 2+信号作用。潜在的好处和应用。站在多个过程的十字路口，定义内-溶酶体Ca 2+信号将：（a）阐明基础科学（Ca 2+信号，信号区室化，内-溶酶体生物学，细胞器/膜动力学，Ca 2+解码）;（B）为更广泛的细胞生物学社区提供新的工具（报告，药理学）;（c）加强细胞器离子通道作为新药物靶点的情况。

项目成果

A cellular protection racket: How lysosomal Ca2+ fluxes prevent kidney injury.

细胞保护球拍：溶酶体 Ca2 通量如何预防肾损伤。

• DOI: 10.1016/j.ceca.2020.102328
• 发表时间: 2021
• 期刊: Cell calcium
• 影响因子: 4
• 作者: Galione A

Choreographing endo-lysosomal Ca2+ throughout the life of a phagosome.

• DOI: 10.1016/j.bbamcr.2021.119040
• 发表时间: 2021-04
• 期刊: Biochimica et biophysica acta. Molecular cell research
• 作者: A. Morgan;Lianne C. Davis;A. Galione

Endolysosomal TPCs regulate social behavior by controlling oxytocin secretion.

• DOI: 10.1073/pnas.2213682120
• 发表时间: 2023-02-14
• 期刊: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• 影响因子: 11.1
• 作者: Martucci, Lora L.;Launay, Jean-Marie;Kawakami, Natsuko;Sicard, Cecile;Desvignes, Nathalie;Dakouane-Giudicelli, Mbarka;Spix, Barbara;Tetu, Maude;Gilmaire, Franck -Olivier;Paulcan, Sloane;Callebert, Jacques;Vaillend, Cyrille;Bracher, Franz;Grimm, Christian;Fossier, Philippe;de la Porte, Sabine;Sakamoto, Hirotaka;Morris, John;Galione, Antony;Granon, Sylvie;Cancela, Jose-Manuel
• 通讯作者: Cancela, Jose-Manuel