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.

CA2+在每个单元格内都有一个必不可少的信号。细胞内部的Ca2+水平非常低，部分原因是它在Ca2+存储的隔间内隔离。为了响应细胞刺激，通过打开驻留离子通道以激活检测器蛋白（“解码器”）和更改细胞过程，从这些商店释放了Ca2+。细胞内Ca2+的增加是几乎所有细胞类型的通用信号，例如为了受精，肌肉收缩，神经冲动，基因表达。最大，最佳理解的Ca2+储存库是内质网（ER），其中包含毫米摩尔Ca2+。 ER Ca2+通道，IP3受体，由第二个信使IP3激活，该Messenger响应细胞刺激（例如激素，神经递质，抗体，抗体，细胞接触）而合成。 IP3合成，IP3R激活和Ca2+释放在刺激后迅速发生。但是，ER并不是唯一的Ca2+储存量，我们发现小的酸性囊泡（包括内体和溶酶体）是重要的Ca2+储存量，但具有与IP3/IP3RS类似的独特的Second Messenger（NAADP）和CA2+通道（TPC）。该轴构成了我们的焦点。尽管它们更称为细胞废物膜，但内部溶质体正在作为动态信号枢纽出现，并响应于环境而整合并传递信号。主要的内部溶质体信号为Ca2+。许多刺激夫妇伴随着溶酶体Ca2+作为转导途径的释放：取决于刺激，细胞合成信使，烟酸腺苷二核苷酸磷酸盐NAADP，它打开了在内鼠散糖体上表达的TPCS（两孔通道）。这些是Ca2+可渗透的，并提高了胞质Ca2+。但是，每个囊泡很小，因此释放的有限量的Ca2+会生成局部Ca2+'纳米域'（局部浓度高，在太空中受到限制）。为什么细胞包含不同的Ca2+存储？答案是，Ca2+在细胞质中并不均匀增加，而是在需要的地方离散地提供。因此，不同商店将Ca2+传递给不同的靶标和不同的下游生理学。我们通过高度局部和特权的对话找到了内部散热体与自己独特的探测器的“配对”，而ER CA2+商店无法替代。因此，每个细胞刺激都为其下游生理选择了适当的Ca2+源。但是，尚不清楚如何生成和解码这些必不可少的内部溶酶体Ca2+信号，从而构成了我们的焦点。 NAADP/TPC轴的定义很差。进一步的复杂性是，内部溶质体小，异质性，运动性和精致定位，在身体/功能上与其他细胞器进行体力相互作用（例如，与ER，Mitochondira）。我们的目标是如何建立和规范这些属于这些属于这些'''''''''''''''''''''''''''''''''''细胞器），从而求解Ca2+特定性难题。显然，目标必须与内散溶性体密切相关，以检测来自TPC的局部“ Ca2+羽流”。我们旨在了解如何将目标带到内部溶血体或相反的情况下如何将内部溶酶体动态带入靶标。我们将确定目标和解码器如何，何时何地与TPC关联。内部溶酶体的放置和运动性对于生理学至关重要，我们还将测试是否有针对不同CA2+信号角色的内部溶质体专家级别。站在多个过程的十字路口上，定义内部溶酶体CA2+信号将：（a）照亮基础科学（CA2+信号，信号，信号室，内部溶酶体生物学，细胞器/膜动力学，CA2+ -Decoding）；作为新药靶标的通道。

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