Dynamic membrane remodeling at invadopodia differentiates invadopodia from podosomes
Dynamic membrane remodeling at invadopodia differentiates invadopodia from podosomes
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DOI：
10.1016/j.ejcb.2010.06.006
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发表时间：
2011-02-01
影响因子：
6.6
通讯作者：
Yamada, Kenneth M.
中科院分区：
文献类型：
--
作者：
Artym, Vira V.;Matsumoto, Kazue;Yamada, Kenneth M.
侵袭伪足是转移性肿瘤和转化细胞的富含肌动蛋白的特殊突起，在 ECM 降解和侵袭中具有重要功能。尽管早期电子显微镜研究将侵袭伪足描述为粘附在基质上的细胞膜的长丝状突起，但荧光显微镜研究主要集中在侵袭伪足作为肌动蛋白-皮质蛋白聚集体定位于 ECM 降解区域。这两种入侵足结构描述缺乏清晰的概念整合，阻碍了对入侵足调控机制的理解。为了确定电子显微镜鉴定的膜丝与侵袭伪足的肌动蛋白-皮质蛋白聚集体之间的关系，我们应用快速活细胞高分辨率全内反射荧光显微镜来检查人类癌细胞侵袭伪足的皮质蛋白核心的细胞膜动力学。我们发现，cortactin 对接到粘附于 2D 纤连蛋白基质的细胞膜上，启动了与侵入足膜过程形成相关的侵入足组装，该侵入足膜过程从腹侧细胞膜腔隙延伸至 ECM。侵入足过程的尖端在与二维基质相互作用时变平，并且随着侵入足的成熟，它会经历持续的快速褶皱和丝状突起的动态形成。为了描述肌动蛋白-皮质蛋白核心和入侵足膜之间新发现的动态关系，我们提出了入侵足复合体模型。使用 TIRF 显微镜，我们还确定，与入侵足形成鲜明对比的是，巨噬细胞足体的膜无法形成任何突起或丝状膜突起。因此，入侵足膜的起伏和皱褶以及从入侵足皮质蛋白核心形成的动态丝状延伸将入侵足定义为与足体不同的入侵上层结构。 (C) 2010 爱思唯尔有限公司。版权所有。
Invadopodia are specialized actin-rich protrusions of metastatic tumor and transformed cells with crucial functions in ECM degradation and invasion. Although early electron microscopy studies described invadopodia as long filament-like protrusions of the cell membrane adherent to the matrix, fluorescence microscopy studies have focused on invadopodia as actin-cortactin aggregates localized to areas of ECM degradation. The absence of a clear conceptual integration of these two descriptions of invadopodial structure has impeded understanding of the regulatory mechanisms that govern invadopodia. To determine the relationship between the membrane filaments identified by electron microscopy and the actin-cortactin aggregates of invadopodia, we applied rapid live-cell high-resolution TIRF microscopy to examine cell membrane dynamics at the cortactin core of the invadopodia of human carcinoma cells. We found that cortactin docking to the cell membrane adherent to 2D fibronectin matrix initiates invadopodium assembly associated with the formation of an invadopodial membrane process that extends from a ventral cell membrane lacuna toward the ECM. The tip of the invadopodial process flattens as it interacts with the 2D matrix, and it undergoes constant rapid ruffling and dynamic formation of filament-like protrusions as the invadopodium matures. To describe this newly discovered dynamic relationship between the actin-cortactin core and invadopodial membranes, we propose a model of the invadopodial complex. Using TIRF microscopy, we also established that - in striking contrast to the invadopodium - membrane at the podosome of a macrophage fails to form any process- or filament-like membrane protrusions. Thus, the undulation and ruffling of the invadopodial membrane together with the formation of dynamic filament-like extensions from the invadopodial cortactin core defines invadopodia as invasive superstructures that are distinct from the podosomes. (C) 2010 Elsevier GmbH. All rights reserved.