Remodelling of cortical actin where lytic granules dock at natural killer cell immune synapses revealed by super-resolution microscopy.
Remodelling of cortical actin where lytic granules dock at natural killer cell immune synapses revealed by super-resolution microscopy.
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DOI：
10.1371/journal.pbio.1001152
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发表时间：
2011-09
期刊：
影响因子：
9.8
通讯作者：
Davis DM
中科院分区：
文献类型：
--
作者：
Brown AC;Oddos S;Dobbie IM;Alakoskela JM;Parton RM;Eissmann P;Neil MA;Dunsby C;French PM;Davis I;Davis DM
超分辨率3D成像揭示了自然杀伤细胞免疫突触处皮质肌动蛋白网络的重塑，这可能对溶解颗粒的分泌很重要。自然杀伤（NK）细胞是先天性免疫细胞，其分泌溶解颗粒以直接杀死病毒感染或穿过免疫突触的转化细胞。然而，在理解这一过程中的一个主要差距是在建立溶解颗粒如何通过已知的NK细胞膜下的皮质肌动蛋白的网格。传统光学显微镜的分辨率太低，无法分辨溶解颗粒分泌过程中的皮质肌动蛋白，这阻碍了研究。在这里，我们使用两种高分辨率成像技术来探测NK细胞受体和丝状（F）-肌动蛋白的突触组织。光镊和活细胞共聚焦显微镜的结合揭示了NKG 2D的微簇在细胞间突触的中心组装成环形结构，Vav 1和Grb 2也在那里积累。在NK细胞蛋白的这种环形组织中，溶解颗粒积聚以供分泌。使用3D结构照明显微镜（3D-SIM）获得100 nm的超分辨率，无论激活或抑制信号占主导地位，在NK细胞突触的中心区域检测到皮质肌动蛋白。引人注目的是，当NK细胞被激活时，在突触的特定区域，皮质肌动蛋白网格的周期性增加。双色超分辨率成像显示，裂解颗粒精确地停靠在这些领域也接近的微管组织中心（MTOC）极化。总之，这些数据表明，皮质肌动蛋白网格的重塑发生在溶细胞NK细胞免疫突触的中心区域。这可能发生在其他类型的细胞分泌中，也强调了新兴的超分辨率成像技术对揭示新生物学的重要性。自然杀伤（NK）细胞是一种免疫细胞，可以识别和杀死病毒感染和癌细胞。这种杀伤需要NK细胞和其靶细胞之间的细胞间接触-称为免疫突触，通过该接触分子可以被递送以触发溶解。NK细胞细胞骨架的重组对于在突触处递送和释放含有溶细胞分子的颗粒是必不可少的。由于我们无法用常规光学显微镜分辨免疫突触处的细胞骨架结构，因此无法准确理解细胞骨架如何参与这些细胞溶解事件。成像技术的最新进展现在提供了看到以前无法检测的细胞结构的分辨率。在这里，我们使用3D超分辨率成像来观察NK免疫突触处的肌动蛋白细胞骨架的结构。我们发现，一个密集的网格肌动蛋白免疫突触的基础上，它是重塑后NK细胞活化。肌动蛋白网络中的结构域打开，指定裂解颗粒停靠的位置以及微管组织中心移动的位置。因此，肌动蛋白重塑发生在分泌过程中的免疫突触，这可能是重要的调节溶解颗粒分泌。
Super-resolution 3D imaging reveals remodeling of the cortical actin meshwork at the natural killer cell immune synapse, which is likely to be important for secretion of lytic granules. Natural Killer (NK) cells are innate immune cells that secrete lytic granules to directly kill virus-infected or transformed cells across an immune synapse. However, a major gap in understanding this process is in establishing how lytic granules pass through the mesh of cortical actin known to underlie the NK cell membrane. Research has been hampered by the resolution of conventional light microscopy, which is too low to resolve cortical actin during lytic granule secretion. Here we use two high-resolution imaging techniques to probe the synaptic organisation of NK cell receptors and filamentous (F)-actin. A combination of optical tweezers and live cell confocal microscopy reveals that microclusters of NKG2D assemble into a ring-shaped structure at the centre of intercellular synapses, where Vav1 and Grb2 also accumulate. Within this ring-shaped organisation of NK cell proteins, lytic granules accumulate for secretion. Using 3D-structured illumination microscopy (3D-SIM) to gain super-resolution of ∼100 nm, cortical actin was detected in a central region of the NK cell synapse irrespective of whether activating or inhibitory signals dominate. Strikingly, the periodicity of the cortical actin mesh increased in specific domains at the synapse when the NK cell was activated. Two-colour super-resolution imaging revealed that lytic granules docked precisely in these domains which were also proximal to where the microtubule-organising centre (MTOC) polarised. Together, these data demonstrate that remodelling of the cortical actin mesh occurs at the central region of the cytolytic NK cell immune synapse. This is likely to occur for other types of cell secretion and also emphasises the importance of emerging super-resolution imaging technology for revealing new biology. Natural Killer (NK) cells are immune cells that can recognise and kill virus-infected and cancerous cells. This killing requires an intercellular contact —termed an immune synapse—between the NK cell and its target cell through which molecules can be delivered to trigger lysis. Reorganisation of the NK cell cytoskeleton is essential for the delivery and release at the synapse of granules containing the cytolytic molecules. Understanding precisely how the cytoskeleton is involved in these cytolytic events has been hampered by our inability to resolve cytoskeletal structure at immune synapses by conventional light microscopy. Very recent advances in imaging technology have now provided the resolving power to see previously undetectable cellular structures. Here, we have used 3D super-resolution imaging to observe the structure of the actin cytoskeleton at the NK immune synapse. We found that a dense mesh of actin underlies the immune synapse and that it is remodelled upon NK cell activation. Domains within the actin meshwork open up specifying where the lytic granules dock and also where the microtubule-organising centre moves towards. Thus, actin remodelling occurs at the immune synapse during secretion and this may be important for the regulation of lytic granule secretion.
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影响因子：
32.4
作者：
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通讯作者：
Shaw, Andrey S.
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9.2
作者：
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影响因子：
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Long EO