Covalent cross-linking of fibronectin to fibrin is required for maximal cell adhesion to a fibronectin-fibrin matrix
Covalent cross-linking of fibronectin to fibrin is required for maximal cell adhesion to a fibronectin-fibrin matrix
复制标题
DOI：
10.1074/jbc.272.40.24999
复制
发表时间：
1997-10-03
影响因子：
4.8
通讯作者：
Schwarzbauer, JE
中科院分区：
文献类型：
--
作者：
Corbett, SA;Lee, L;Schwarzbauer, JE
在血凝块中，纤维蛋白和血浆纤连蛋白 (pFN) 通过活化的因子 XIII（因子 XIIIa）共价交联，形成 pFN-纤维蛋白多聚体。为了确定共价 pFN-纤维蛋白相互作用的功能意义，我们开发了一种体外模型，该模型允许将重组 FN (recFN) 分子掺入共价交联的结构中。 recFN-纤维蛋白基质，使用杆状病毒表达系统，我们表达了由氨基末端70-kDa区域和前11个III型重复序列（WT）组成的recFN单体，其中谷氨酰胺在位置3和4（Q2）或位置3、4和16（Q3）处发生突变，检查这些recFN与纤维蛋白凝块的共价掺入证实了这一点 谷氨酰胺 3 和 4 是 FN-纤维蛋白交联的主要参与者，因为这些位点的突变使交联效率降低了 65%。然而，16 位谷氨酰胺的额外突变消除了 >99% 的交联，表明它也可能是因子 XIIIa 反应性的。当 Q3 recFN-纤维蛋白凝块用作细胞粘附的底物时，与 WT recFN-纤维蛋白凝块相比，细胞附着和扩散均有所减少。这些数据表明，为了最大程度地细胞附着到 FN-纤维蛋白凝块，FN 必须通过因子 XIIIa 与纤维蛋白交联。
In a blood clot, fibrin and plasma fibronectin (pFN) are covalently cross linked by activated factor XIII (factor XIIIa) to form pFN-fibrin multimers, To determine the functional significance of covalent pFN-fibrin interactions, we have developed an in vitro model which allows the incorporation of recombinant FN (recFN) molecules into a covalently cross-linked recFN-fibrin matrix, Using the baculovirus expression system, we have expressed recFN monomers composed of the amino-terminal 70-kDa region and the first 11 type III repeats (WT) with mutations in the glutamines at positions 3 and 4 (Q2) or at 3, 4, and 16 (Q3), Examination of the covalent incorporation of these recFNs into fibrin clots confirms that glutamines 3 and 4 are major participants in FN-fibrin cross-linking as the mutation of these sites reduces cross-linking efficiency by 65%. Additional mutation of the glutamine at position 16, however, eliminates >99% of cross-linking suggesting that it also may be factor XIIIa reactive, When the Q3 recFN-fibrin clots were used as substrates for cell adhesion, there was a decrease in both cell attachment and spreading when compared with the WT recFN-fibrin clots, These data demonstrate that for maximal cell attachment to a FN-fibrin clot, FN must be cross-linked to fibrin by factor XIIIa.