INTEGRIN AND ARG GLY ASP DEPENDENCE OF CELL-ADHESION TO THE NATIVE AND UNFOLDED TRIPLE-HELIX OF COLLAGEN TYPE-VI
INTEGRIN AND ARG GLY ASP DEPENDENCE OF CELL-ADHESION TO THE NATIVE AND UNFOLDED TRIPLE-HELIX OF COLLAGEN TYPE-VI
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DOI：
10.1006/excr.1993.1134
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发表时间：
1993-05-01
影响因子：
3.7
通讯作者：
TIMPL, R
中科院分区：
文献类型：
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作者：
PFAFF, M;AUMAILLEY, M;TIMPL, R
胃蛋白酶溶解的胶原VI的三螺旋和热变性，展开的形式，以促进Mg 2+和Mn 2+依赖的附着和扩散的各种细胞系。除了A375黑色素瘤细胞的情况外，在三螺旋底物上，用几种合成的RGD肽没有观察到细胞粘附的抑制。相反，粘附到未折叠的基板是高度敏感的RGD抑制。根据人胶原α1（VI）、α2（VI）和α3（VI）链的三螺旋序列中存在的10个RGD序列设计了9个合成肽。只有一种肽（对应于α3（VI）链的C-末端）显示出显著的抑制活性，而当用作白蛋白缀合物时，几种肽在直接粘附试验中具有活性。采用整联蛋白亚基抗体抑制试验、亲和色谱法和与纯化整联蛋白（α1β1、α2β1、αVβ3和αIIbβ3）的配体结合来鉴定胶原VI受体。与三螺旋底物的结合由α1β1和α2β1整联蛋白介导。两种整合素与胶原VI的结合弱于与胶原I和/或IV的结合。对变性底物的识别由β1和β3整联蛋白介导。对α5β1和αVβ3显示出活性，对αIIbβ3显示出弱活性，但未鉴定出所有可能涉及的α亚基。不同的受体组也参与A375细胞与三螺旋（β1介导）和变性（β3介导）胶原VI的结合，即使在这种情况下，两种相互作用都可以被RGD肽有效抑制。
Pepsin-solubilized collagen VI in triple-helical and heat-denatured, unfolded form was shown to promote Mg2+- and Mn2+-dependent attachment and spreading of various cell lines. On the triple-helical substrate no inhibition of cell adhesion was observed with several synthetic RGD peptides except in the case of A375 melanoma cells. In contrast, adhesion to the unfolded substrate was highly sensitive to RGD inhibition. Nine synthetic peptides were designed according to 10 RGD sequences present in the triple-helical sequence of human collagen α1(VI), α2(VI), and α3(VI) chains. Only one peptide, corresponding to the C-terminal end of α3(VI) chain, showed substantial inhibitory activity, whereas several peptides were active in direct adhesion assays when used as albumin conjugates. Inhibition tests with antibodies to integrin subunits, affinity chromatography, and ligand binding with purified integrins (α1β1, α2β1, αVβ3, and αIIbβ3) were used to identify collagen VI receptors. Binding to the triple-helical substrate is mediated by α1β1 and α2β1 integrins. Binding of both integrins to collagen VI was weaker than that to collagens I and/or IV. Recognition of the denatured substrate is mediated by β1 and β3 integrins. Activity was shown for α5β1 and αVβ3 and weakly for αIIbβ3 but not all α subunits possibly involved were identified. Distinct sets of receptors were also involved in A375 cell binding to triple-helical (β1-mediated) and denatured (β3-mediated) collagen VI, even though in this case both interactions could be efficiently inhibited by RGD peptides.