Identification of the heparin-binding determinants within fibronectin repeat III - Role in cell spreading and growth
Identification of the heparin-binding determinants within fibronectin repeat III - Role in cell spreading and growth
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DOI：
10.1074/jbc.m608611200
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发表时间：
2006-11-17
影响因子：
4.8
通讯作者：
Hocking, Denise C.
中科院分区：
文献类型：
--
作者：
Gui, Liqiong;Wojciechowski, Katherine;Hocking, Denise C.
纤连蛋白是高分子量的糖蛋白，其作为可溶性分子在血液中循环，并且还以不溶性的多聚体形式存在于整个身体的细胞外基质中。可溶性纤连蛋白通过细胞依赖性过程聚合成不溶性细胞外基质（ECM）原纤维。最近的研究表明，细胞与ECM形式的纤连蛋白的相互作用促进肌动蛋白组织和细胞收缩性，增加细胞生长和迁移，并增强人工组织构建体的拉伸强度;单独连接整合素不足以触发这些反应。有证据表明，ECM纤连蛋白对细胞功能的影响部分是由第一个III 1重复序列（FNIII 1）内的基质结合肝素结合位点介导的。在这项研究中，我们将FNIII 1的肝素结合活性定位于一组碱性氨基酸，Arg（613），Trp（614），Arg（615）和Lys（617）。工程化以模拟ECM形式的纤连蛋白的重组纤连蛋白构建体的定点诱变证明这些残基对于刺激细胞铺展和增加细胞增殖也是关键的。细胞增殖与细胞面积密切相关。使用整合素和肝素结合的纤连蛋白突变体，我们发现细胞的传播和生长之间的正相关性时，细胞亚最大限度地传播ECM蛋白包被的表面上的治疗时间。然而，细胞最大限度地传播玻连蛋白或纤连蛋白仍然响应纤连蛋白基质模拟物的增长，表明细胞面积的绝对变化是不需要的martricryptic网站FNIII 1诱导的细胞增殖的增加。
Fibronectins are high molecular mass glycoproteins that circulate as soluble molecules in the blood, and are also found in an insoluble, multimeric form in extracellular matrices throughout the body. Soluble fibronectins are polymerized into insoluble extracellular matrix (ECM) fibrils via a cell-dependent process. Recent studies indicate that the interaction of cells with the ECM form of fibronectin promotes actin organization and cell contractility, increases cell growth and migration, and enhances the tensile strength of artificial tissue constructs; ligation of integrins alone is insufficient to trigger these responses. Evidence suggests that the effect of ECM fibronectin on cell function is mediated in part by a matricryptic heparin-binding site within the first III1 repeat (FNIII1). In this study, we localized the heparin- binding activity of FNIII1 to a cluster of basic amino acids, Arg(613), Trp(614), Arg(615), and Lys(617). Site- directed mutagenesis of a recombinant fibronectin construct engineered to mimic the ECM form of fibronectin demonstrates that these residues are also critical for stimulating cell spreading and increasing cell proliferation. Cell proliferation has been tightly correlated with cell area. Using integrin-and heparin-binding fibronectin mutants, we found a positive correlation between cell spreading and growth when cells were submaximally spread on ECM protein-coated surfaces at the time of treatment. However, cells maximally spread on vitronectin or fibronectin still responded to the fibronectin matrix mimetic with an increase in growth, indicating that an absolute change in cell area is not required for the increase in cell proliferation induced by the matricryptic site of FNIII1.