Association of hnRNP S1 proteins with vimentin intermediate filaments in migrating cells
Association of hnRNP S1 proteins with vimentin intermediate filaments in migrating cells
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DOI：
10.1242/jcs.02345
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发表时间：
2005-05-15
影响因子：
4
通讯作者：
Kaneda, K
中科院分区：
文献类型：
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作者：
Inoue, A;Watanabe, T;Kaneda, K
S1蛋白C2和D2是多功能的hnRNP蛋白，在细胞核中充当转录调节因子。在培养中的各种细胞的免疫荧光染色显示，S1蛋白也出现在细胞质中，往往与波形蛋白中间丝（VFs）。在这里，我们验证了协会的S1蛋白与波形蛋白使用波形蛋白缺陷细胞，交联和免疫沉淀，并进一步研究了这种协会的生物学意义。VF上的SI蛋白，这里称为SI纤维，在高度融合的细胞中丢失，其中细胞增殖和细胞代谢活性由于细胞密度依赖性停滞而大大降低。然而，S1纤维的消失与这些活动的减少无关，而是与细胞迁移的抑制有关。尽管在非迁移组织的细胞以及汇合培养的细胞中未检测到S1纤维，但在检查的所有迁移细胞中均发现了S1纤维，例如划痕/伤口实验中的培养细胞、血液中性粒细胞和单核细胞以及参与组织愈合的成纤维细胞。此外，S1纤维出现时，即使在汇合的细胞诱导VF重组冈田酸。我们建议，S1蛋白与迁移细胞中的VF相关。S1蛋白的形成/重组的VF的可能参与进行了讨论。
S1 proteins C2 and D2 are multifunctional hnRNP proteins acting as transcriptional regulators in the nucleus. Immunofluorescence staining of various cells in culture revealed that S1 proteins also occur in the cytoplasm, often in association with vimentin intermediate filaments (VFs). Here, we verified the association of S1 proteins with vimentin using vimentin-deficient cells, crosslinking and immunoprecipitation, and further investigated the biological significance of this association. SI proteins on VFs, referred to here as SI fibers, were lost in highly confluent cells, where cell proliferation and cellular metabolic activity greatly decreased owing to cell density-dependent arrest. However, the disappearance of S1 fibers was not related to these reduced activities, but to inhibited cell migration. Although undetected in cells of non-migratory tissues as well as in confluent cultured cells, S1 fibers were found in all migratory cells examined, such as cultured cells in scratch/wound experiments, blood neutrophils and monocytes, and fibroblasts engaging in tissue healing. In addition, S1 fibers reappeared even in confluent cells when VFs were induced to reorganize with okadaic acid. We propose that S1 proteins occur in association with VFs in migratory cells. Possible participation of S1 proteins in the formation/reorganization of VFs is discussed.