Heparan sulfate is necessary for the early formation of nascent fibronectin and collagen I fibrils at matrix assembly sites.
Heparan sulfate is necessary for the early formation of nascent fibronectin and collagen I fibrils at matrix assembly sites.
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DOI：
10.1016/j.jbc.2021.101479
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发表时间：
2022-01
期刊：
影响因子：
--
通讯作者：
Schwarzbauer JE
中科院分区：
文献类型：
--
作者：
Hill KE;Lovett BM;Schwarzbauer JE
纤连蛋白（FN）是细胞外基质（ECM）的重要组成部分，通过细胞介导的过程组装，其中整合素受体结合分泌的FN并介导其聚合成在细胞之间延伸的原纤维，最终形成不溶性基质。我们以前的工作，使用突变的中国仓鼠卵巢（CHO）细胞鉴定的糖胺聚糖硫酸乙酰肝素（HS）和它的结合FN作为必不可少的不溶性FN纤维的形成。在这项研究中，我们调查的贡献HS在装配过程的早期阶段，使用敲低exostosin-1（EXT 1），HS链合成所需的糖基转移酶之一。EXT 1表达降低的NIH 3 T3成纤维细胞在不溶性基质中的FN和I型胶原蛋白均显着减少。我们发现，FN原纤维的形成是在基质组装位点开始的，而这些位点是由EXT 1敲低的细胞形成的，与野生型细胞相比，它们的生长受到阻碍。观察到的最严重的缺陷是新生FN原纤维的聚合，在EXT 1敲除后，其减少了2.5倍。通过添加足够长的外源性可溶性肝素链以同时结合多个FN分子来挽救该缺陷。在这个过程中的可溶性肝素的活性表明，新生原纤维的形成更依赖于HS比一个特定的HS蛋白聚糖的蛋白质组分。总之，我们的研究结果表明，肝素或HS是必要的FN分子在早期原纤维组装的网站集中和本地化。
Fibronectin (FN), an essential component of the extracellular matrix (ECM), is assembled via a cell-mediated process in which integrin receptors bind secreted FN and mediate its polymerization into fibrils that extend between cells, ultimately forming an insoluble matrix. Our previous work using mutant Chinese hamster ovary (CHO) cells identified the glycosaminoglycan heparan sulfate (HS) and its binding to FN as essential for the formation of insoluble FN fibrils. In this study, we investigated the contributions of HS at an early stage of the assembly process using knockdown of exostosin-1 (EXT1), one of the glycosyltransferases required for HS chain synthesis. NIH 3T3 fibroblasts with decreased EXT1 expression exhibited a significant reduction in both FN and type I collagen in the insoluble matrix. We show that FN fibril formation is initiated at matrix assembly sites, and while these sites were formed by cells with EXT1 knockdown, their growth was stunted compared with wild-type cells. The most severe defect observed was in the polymerization of nascent FN fibrils, which was reduced 2.5-fold upon EXT1 knockdown. This defect was rescued by the addition of exogenous soluble heparin chains long enough to simultaneously bind multiple FN molecules. The activity of soluble heparin in this process indicates that nascent fibril formation depends on HS more so than on the protein component of a specific HS proteoglycan. Together, our results suggest that heparin or HS is necessary for concentrating and localizing FN molecules at sites of early fibril assembly.
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DOI：
10.1073/pnas.0705807105
发表时间：
2008-03-25
影响因子：
11.1
作者：
Presto, Jenny;Thuveson, Maria;Kjellen, Lena
通讯作者：
Kjellen, Lena
影响因子：
6.9
作者：
Reitman, Irene;Huang, Mia L.;Schwarzbauer, Jean E.
通讯作者：
Schwarzbauer, Jean E.
影响因子：
5.5
作者：
Sottile, Jane;Shi, Feng;Chandler, Jennifer
通讯作者：
Chandler, Jennifer
影响因子：
7.5
作者：
Kadler KE;Hill A;Canty-Laird EG
通讯作者：
Canty-Laird EG
影响因子：
7.2
作者：
Sarrazin, Stephane;Lamanna, William C.;Esko, Jeffrey D.
通讯作者：
Esko, Jeffrey D.