Dynamic actin-mediated nano-scale clustering of CD44 regulates its meso-scale organization at the plasma membrane
Dynamic actin-mediated nano-scale clustering of CD44 regulates its meso-scale organization at the plasma membrane
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DOI：
10.1091/mbc.e18-11-0715
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发表时间：
2019-08
影响因子：
3.3
通讯作者：
Parijat Sil;N. Mateos;S. Nath;S. Buschow;C. Manzo;Kenichi G. N. Suzuki;T. Fujiwara;A. Kusumi;
中科院分区：
文献类型：
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作者：
Parijat Sil;N. Mateos;S. Nath;S. Buschow;C. Manzo;Kenichi G. N. Suzuki;T. Fujiwara;A. Kusumi;
细胞表面的跨膜黏附受体，如CD44，通常配有与细胞外基质(ECM)和细胞内细胞骨架机械相互作用的模块。CD44最近被证明通过充当膜纠察器将膜划分为不同的区域，从而促进信号受体的功能。虽然膜蛋白的空间组织和扩散研究通常是分开进行的，但在这里，我们通过对活细胞的高时空分辨率成像来结合组织和扩散的观察，揭示了CD44的分级组织。CD44以介观网络模式存在，表现出增强的限制作用，并沿其边界富含CD44的纳米团簇。这种纳米聚集是由潜在的皮质肌动蛋白动力学协调的。肌动蛋白与肌动蛋白的相互作用是由细胞内域(ICD)的特定片段介导的。这影响了蛋白质在纳米尺度上的组织，产生了对Forin的选择性要求，而不是基于Arp2/3的肌动蛋白成核机制。胞外区(ECD)及其与ECM元素的相互作用不影响中尺度的组织，但可能起到相对于ECM重新定位网络的作用。综上所述，我们的结果捕捉到了CD44在细胞表面组织的分层性质，活性细胞骨架模板化的纳米团定位于中尺度的网络模式。
Transmembrane adhesion receptors at the cell surface, such as CD44, are often equipped with modules to interact with the extracellular-matrix(ECM) and the intra-cellular cytoskeletal machinery. CD44 has been recently shown to compartmentalize the membrane into domains by acting as membrane pickets, facilitating the function of signaling receptors. While spatial organization and diffusion studies of membrane proteins are usually conducted separately, here we combine observations of organization and diffusion by using high spatio-temporal resolution imaging on living cells to reveal a hierarchical organization of CD44. CD44 is present in a meso-scale meshwork pattern where it exhibits enhanced confinement and is enriched in nano-clusters of CD44 along its boundaries. This nanoclustering is orchestrated by the underlying cortical actin dynamics. Interaction with actin is mediated by specific segments of the intracellular-domain(ICD). This influences the organization of the protein at the nano-scale, generating a selective requirement for formin over Arp2/3-based actin-nucleation machinery. The extracellular-domain(ECD) and its interaction with elements of ECM do not influence the meso-scale organization, but may serve to reposition the meshwork with respect to the ECM. Taken together, our results capture the hierarchical nature of CD44 organization at the cell surface, with active cytoskeleton-templated nano-clusters localized to a meso-scale meshwork pattern.