The NCI domain of collagen IV encodes a novel network composed of the α1, α2, α5, and α6 chains in smooth muscle basement membranes
The NCI domain of collagen IV encodes a novel network composed of the α1, α2, α5, and α6 chains in smooth muscle basement membranes
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DOI：
10.1074/jbc.m103690200
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发表时间：
2001-07-27
影响因子：
4.8
通讯作者：
Hudson, BG
中科院分区：
文献类型：
--
作者：
Borza, DB;Bondar, O;Hudson, BG
IV型胶原是基底膜（BM）的主要成分，是具有组织特异性分布的六条同源链（α 1-α 6）的家族。链组装成链组成不同的超分子网络。在这项研究中，一个新的网络被确定和主动脉和膀胱平滑肌BM的特点。通过亲和色谱法使用针对α 5和α 6 NC 1结构域的单克隆抗体对通过胶原酶消化溶解的非胶原（NC 1）六聚体进行分级，然后通过二维凝胶电泳和Western印迹进行表征。发现这两种BM除了经典的α 1. α 2网络之外还包含新的α 1. α 2. α 5. α 6网络。α 1. α 2. α 5. α 6网络代表一种新的排列，其中含有α 5和α 6链的原聚体（三螺旋同种型）通过NC 1-NC 1相互作用连接到由α 1和α 2链组成的相邻原聚体。重新关联的研究表明，NCI域包含识别序列足以编码这两个网络的组装。这些发现与先前的发现一起表明IV型胶原的六条链分布在三个主要网络（α 1. α 2. α 3. α 4. α 5和α 1. α 2. α 5. α 6）中，其链组成由NCI结构域编码。α 1. α 2. α 5. α 6网络的存在为X连锁Alport综合征患者BM中α 5和α 6链的伴随丢失提供了分子解释。
Type IV collagen, the major component of basement membranes (BMs), is a family of six homologous chains (alpha1-alpha6) that have a tissue-specific distribution. The chains assemble into supramolecular networks that differ in the chain composition. In this study, a novel network was identified and characterized in the smooth muscle BMs of aorta and bladder. The noncollagenous (NC1) hexamers solubilized by collagenase digestion were fractionated by affinity chromatography using monoclonal antibodies against the alpha5 and alpha6 NC1 domains and then characterized by two-dimensional gel electrophoresis and Western blotting. Both BMs were found to contain a novel alpha1.alpha2.alpha5.alpha6 network besides the classical alpha1.alpha2 network. The alpha1.alpha2.alpha5.alpha6 network represents a new arrangement in which a protomer (triple-helical isoform) containing the alpha5 and alpha6 chains is linked through NC1-NC1 interactions to an adjoining protomer composed of the alpha1 and alpha2 chains. Re-association studies revealed that the NCI domains contain recognition sequences sufficient to encode the assembly of both networks. These findings, together with previous ones, indicate that the six chains of type IV collagen are distributed in three major networks (alpha1.alpha2 alpha3.alpha4.alpha5, and alpha1.alpha2.alpha5.alpha6) whose chain composition is encoded by the NCI domains. The existence of the alpha1.alpha2.alpha5.alpha6 network provides a molecular explanation for the concomitant loss of alpha5 and alpha6 chains from the BMs of patients with X-linked Alport's syndrome.