Syndecan-1 mediates cell spreading in transfected human lymphoblastoid (Raji) cells.
Syndecan-1 mediates cell spreading in transfected human lymphoblastoid (Raji) cells.
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DOI：
10.1083/jcb.132.6.1209
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发表时间：
1996-03
期刊：
影响因子：
--
通讯作者：
Rapraeger AC
中科院分区：
文献类型：
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作者：
Lebakken CS;Rapraeger AC
Syndecan-1是一种细胞表面蛋白聚糖，含有高度保守的跨膜和胞质结构域，以及含有硫酸乙酰肝素糖胺聚糖的胞外结构域。通过这些结构域，syndecan-1被认为在生长因子作用、细胞外基质粘附和控制细胞形态的细胞骨架组织中具有作用。为了研究syndecan-1在细胞粘附和细胞骨架重组中的作用，将小鼠syndecan-1 cDNA转染到人Raji细胞中，Raji细胞是一种淋巴母细胞样细胞系，其作为悬浮细胞生长，并且表现出很少或没有内源性细胞表面硫酸乙酰肝素。高表达转染子（Raji-Sl细胞）结合并在固定的血小板反应蛋白或纤连蛋白上扩散，所述血小板反应蛋白或纤连蛋白是蛋白聚糖的硫酸乙酰肝素链的配体。这种结合和扩散由于不依赖于核心蛋白质的胞质结构域，是表达具有胞质缺失的核心蛋白质的突变体保持扩散的能力。该扩散通过多配体蛋白聚糖-1核心蛋白的接合介导，因为Raji-S1细胞还结合到固定的mAb 281.2上并在其上扩散，所述mAb 281.2是对多配体蛋白聚糖-1核心蛋白的胞外域具有特异性的抗体。在抗体上的扩散不依赖于硫酸乙酰肝素糖胺聚糖链，并且可以通过与可溶性mAb 281.2竞争来抑制。细胞松弛素D或秋水仙素处理可抑制其扩散。这些数据表明，syndecan-1的核心蛋白通过在细胞表面形成多分子信号复合物来介导扩散，该信号复合物发出细胞骨架重组的信号。该复合物可以通过与多配体蛋白聚糖核心蛋白的膜内或细胞外相互作用形成。
Syndecan-1 is a cell surface proteoglycan containing a highly conserved transmembrane and cytoplasmic domain, and an extracellular domain bearing heparan sulfate glycosaminoglycans. Through these domains, syndecan-1 is proposed to have roles in growth factor action, extracellular matrix adhesion, and cytoskeletal organization that controls cell morphology. To study the role of syndecan-1 in cell adhesion and cytoskeleton reorganization, mouse syndecan-1 cDNA was transfected into human Raji cells, a lymphoblastoid cell line that grows as suspended cells and exhibits little or no endogenous cell surface heparan sulfate. High expressing transfectants (Raji-Sl cells) bind to and spread on immobilized thrombospondin or fibronectin, which are ligands for the heparan sulfate chains of the proteoglycan. This binding and spreading as not dependent on the cytoplasmic domain of the core protein, is mutants expressing core proteins with cytoplasmic deletions maintain the ability to spread. The spreading is mediated through engagement of the syndecan-1 core protein, as the Raji-S 1 cells also bind to and spread on immobilized mAb 281.2, an antibody specific for the ectodomain of the syndecan-1 core protein. Spreading on the antibody is independent of the heparan sulfate glycosaminoglycan chains and can be inhibited by competition with soluble mAb 281.2. The spreading can be inhibited by treatment with cytochalasin D or colchicine. These data suggest that the core protein of syndecan-1 mediates spreading through the formation of a multimolecular signaling complex at the cell surface that signals cytoskeleton reorganization. This complex may form via intramembrane or extracellular interactions with the syndecan core protein.