NC1 domain of type VII collagen binds to the β3 chain of laminin 5 via a unique subdomain within the fibronectin-like repeats
NC1 domain of type VII collagen binds to the β3 chain of laminin 5 via a unique subdomain within the fibronectin-like repeats
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DOI：
10.1046/j.1523-1747.1999.00491.x
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发表时间：
1999-02-01
影响因子：
6.5
通讯作者：
Woodley, DT
中科院分区：
文献类型：
--
作者：
Chen, M;Marinkovich, MP;Woodley, DT
VII型胶原是锚定原纤维的主要成分，由一个中心胶原三螺旋结构域和两个非胶原球状结构域NC1和NC2组成，大约50%的分子质量被NC1结构域消耗。我们之前证明了NC1与多种细胞外基质成分结合，包括层粘连蛋白5和层粘连蛋白6的复合物（Chen等人，1997a）。在本研究中，我们研究了NC1与层粘连蛋白5（锚定丝的一种成分）的相互作用。通过酶联免疫吸附试验和i -125放射性标记的NC1与层粘连蛋白5包被孔的结合，检测了真实的和纯化的重组NC1与人和大鼠层粘连蛋白5的结合，但不与层粘连蛋白1或白蛋白结合。NC1主要与层粘连蛋白5的β 3链结合，但也与γ 2链结合。I-125-NC1与层粘连蛋白5的结合被50倍过量的未标记的NC1或去糖基化的NC1以及层粘连蛋白5的多克隆抗体或β 3链的单克隆抗体所抑制。利用NC1缺失突变体重组蛋白，NC1的285 AA（残基760-1045）亚结构域被鉴定为层粘连蛋白5的结合位点，来自大泡性表皮松解症血清的IgG含有与层粘连蛋白5结合位点共定位的NC1表位自身抗体，抑制了NC1与层粘连蛋白5的结合。nc1 -层粘连蛋白5相互作用的扰动可能与大疱性表皮松解的发病机制有关。
Type VII collagen, the major component of anchoring fibrils, consists of a central collagenous triple-helical domain flanked by two noncollagenous, globular domains, NC1 and NC2, Approximately 50% of the molecular mass of the molecule is consumed by the NC1 domain. We previously demonstrated that NC1 binds to various extracellular matrix components including a complex of laminin 5 and laminin 6 (Chen er al, 1997a), In this study, we examined the interaction of NC1 with laminin 5 (a component of anchoring filaments), Both authentic and purified recombinant NC1 bound to human and rat laminin 5 as measured by enzyme-linked immunosorbant assay and by binding of I-125-radiolabeled NC1 to laminin 5-coated wells, but not to laminin 1 or albumin. NC1 bound predominantly to the beta 3 chain of laminin 5, but also to the gamma 2 chain when examined by a protein overlay assay, The binding of I-125-NC1 to laminin 5 was inhibited by a 50-fold excess of unlabeled NC1 or de-glycosylated NC1, as well as a polyclonal antibody to laminin 5 or a monoclonal antibody to the beta 3 chain. In contrast, the NC1-laminin 5 interaction was not affected by a monoclonal antibody to the alpha 3 chain, Using NC1 deletion mutant recombinant proteins, a 285 AA (residues 760-1045) subdomain of NC1 was identified as the binding site for laminin 5, IgG from an epidermolysis bullosa acquisita serum containing autoantibodies to epitopes within NC1 that colocalized with the laminin 5 binding site inhibited the binding of NC1 to laminin 5, Thus, perturbation of the NC1-laminin 5 interaction may contribute to the pathogenesis of epidermolysis bullosa acquisita.