Specificity in the interactions of extracellular matrix proteins with subpopulations of the glycosaminoglycan heparin.
Specificity in the interactions of extracellular matrix proteins with subpopulations of the glycosaminoglycan heparin.
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细胞外基质蛋白与糖胺聚糖肝素亚群相互作用的特异性。
DOI：
10.1021/bi00069a008
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发表时间：
1993
期刊：
影响因子：
2.9
通讯作者：
Lander,AD
中科院分区：
文献类型：
--
作者：
SanAntonio,JD;Slover,J;Lawler,J;Karnovsky,MJ;Lander,AD
摘要：许多细胞外基质糖蛋白，包括层粘连蛋白、纤维连接蛋白、血小板反应蛋白、I型胶原蛋白和其他胶原蛋白，可以与糖胺聚糖肝素结合，但对这些相互作用的功能意义所知甚少。目前还不清楚肝素结合细胞外基质蛋白是否识别肝素中不同的结构元素，也不知道所有细胞外基质蛋白是否识别肝素结构的相同或不同方面。如果细胞外基质蛋白都能识别肝素的不同特征，那么这种特异性在体内可能很重要，因为体内存在结构上不同的硫酸肝素种类。为了研究细胞外基质蛋白与肝素结合的特异性，采用亲和共电泳（ACE）方法[Lee， M. K., & Lander, AD (1991) Proc. Natl.]。学会科学。[j].中国科学院学报（自然科学版）。低MT (~ 6 kDa) 125i -肝素通过含有不同浓度细胞外基质蛋白的琼脂糖凝胶道电泳分离；从肝素迁移模式，结合亲和力计算。结果表明，纤维连接蛋白、I型胶原蛋白和层粘连蛋白（而不是凝血反应蛋白）都能将肝素分解成亚群，这些亚群在结合亲和力上存在很大差异。从含有纤维连接蛋白、I型胶原蛋白或层粘连蛋白的ACE凝胶中分离出肝素的部分，这些部分代表了与这些蛋白质结合最强烈的25%分子和最不强烈结合的25%分子。随后对这六个部分的ACE分析表明：(1)对于纤维连接蛋白、I型胶原蛋白和层粘连蛋白，强结合和弱结合的肝素亚组分在Ki\中差异约5-30倍(2)与纤维连接蛋白、I型胶原蛋白或层粘连蛋白中的任何一种强结合的肝素也与其他两种强结合；(3)肝素与纤维连接蛋白、ⅰ型胶原蛋白或层粘连蛋白中的任何一种结合较弱，与其他两种结合也较弱；(4)肝素亚组分对纤维连接蛋白、I型胶原和层粘连蛋白的亲和力差异很大，但对血栓反应蛋白或肝素结合生长因子碱性成纤维细胞生长因子（bFGF）的K&差异不大；(5)分子电荷的异质性（通过二乙基氨基乙基（DEAE）色谱法测量）、大小、抗凝血酶III识别序列的存在与否都不能解释肝素亚群与纤维连接蛋白、I型胶原蛋白和层粘连蛋白的选择性结合。这些结果表明肝素内的结构元件可以优先结合细胞外基质蛋白。一些（但不是全部）细胞外基质蛋白对这些结构特征的敏感性表明，类似的特征，如果存在于硫酸肝素或其他糖胺聚糖中，可能与体内的生理相关。肝素结合蛋白由一组不同的分子组成，在细胞外基质结构和功能、细胞粘附、生长和分化中发挥重要作用[参见Ruoslahti（1988）和jackson等人（1991）的综述]。大多数肝素结合蛋白的正常配体被认为是在细胞外基质和细胞表面蛋白聚糖上发现的硫酸肝素链。硫酸乙酰肝素和其他糖胺聚糖一样，由糖醛酸和氨基糖二糖亚基的线性主链组成，它们具有不同的长度和不同的复杂修饰模式，如外映化和n -和o -磺化。通过研究蛋白质片段、合成肽和化学修饰或诱变修饰的蛋白质的肝素结合特性，已经部分阐明了控制肝素结合的蛋白质结构特征[例如，参见…]
Revised Manuscript Received February 9, 1993 abstract: Many extracellular matrix glycoproteins—including laminin, fibronectin, thrombospondin, type I collagen, and other collagens—bind the glycosaminoglycan heparin, yet little is known about the functional significance of these interactions. It is also not known if heparin-binding extracellular matrix proteins recognize distinct structural elements in heparin, nor whether all extracellular matrix proteins recognize the same or different aspects of heparin structure. If extracellular matrix proteins each recognize distinct features of heparin, such specificity could be of importance in vivo, where structurally distinct heparan sulfate species occur. To investigate specificity in the binding between extracellular matrix proteins and heparin, the method of affinity coelectrophoresis (ACE) was used [Lee, M. K., & Lander, AD (1991) Proc. Natl. Acad. Sci. USA 88, 2768-2772]. Low MT (~ 6 kDa) 125I-heparin was fractionated by electrophoresis through agarose gel lanes containing extracellular matrix proteins at various concentrations; from heparin migration patterns, binding affinities were calculated. The results indicate that fibronectin, type I collagen, and laminin—but not thrombospondin—eachfractionate heparin into subpopulations that differ substantially in binding affinity. From ACE gels containing either fibronectin, type I collagen, or laminin, fractions of heparin were isolated that represent the 25% of molecules most strongly bound and the 25% least strongly bound by each of these proteins. Subsequent ACE analysis of these six fractions showed that (1) for each of fibronectin, type I collagen, and laminin, strongly-and weakly-binding heparin subfractions differ~5-30-fold in Ki\(2) heparin that binds strongly to any one of fibronectin, type I collagen, or laminin also binds strongly to the other two;(3) heparin that binds weakly to any one of fibronectin, type I collagen, or laminin, also binds weakly to the other two;(4) heparin subfractions that differ greatly in affinity for fibronectin, type I collagen, and laminin show little difference in K& for thrombospondin or for the heparin-binding growth factor basic fibroblast growth factor (bFGF);(5) neither heterogeneity in molecular charge [as measuredby diethylaminoethyl (DEAE) chromatography] nor size nor the presence or absence of antithrombin III recognition sequences can account for the selective binding of heparin subpopulations to fibronectin, type I collagen, and laminin. These results suggest that structural elements within heparin can confer preferential binding to extracellular matrix proteins. Sensitivity of some, but not all, extracellular matrix proteinsto these structural features suggests that similar features, if present in heparan sulfates or other glycosaminoglycans, may be physiologically relevant in vivo.Heparin-binding proteins comprise a diverse group of molecules that perform important roles in extracellular matrix structure and function, cell adhesion, growth, and differen-tiation [see Ruoslahti (1988) andJackson et al.(1991) for reviews]. The normal ligands of most heparin-binding proteins are believed to be heparan sulfate chains found on extracellular matrix and cell-surface proteoglycans. Heparan sulfates, like other glycosaminoglycans, consist of a linear backbone of uronic acid and amino sugar disaccharide subunits, of varying lengths and with varyingpatterns of complex modifications, such as epimerization and N-and O-sulfation. Features of protein structure that control heparin binding have been partially elucidated by studying the heparin-binding properties of protein fragments, synthetic peptides, and proteins modified chemically or by mutagenesis [eg, see …