Identification of an α3β1 integrin recognition sequence in thrombospondin-1
Identification of an α3β1 integrin recognition sequence in thrombospondin-1
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DOI：
10.1074/jbc.274.34.24080
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发表时间：
1999-08-20
影响因子：
4.8
通讯作者：
Roberts, DD
中科院分区：
文献类型：
--
作者：
Krutzsch, HC;Choe, BJ;Roberts, DD
含有凝血酶敏感蛋白-L(TSP1)第190-201位氨基酸残基的合成肽在固定化时可促进MDAMB-435乳腺癌细胞的黏附，而在溶液中加入TSP1则可抑制该细胞与TSP1的黏附。β(1)整合素激活抗体、Mn2+和胰岛素样生长因子I可增强与该多肽的粘附性，而α(3)β(1)整合素功能阻断抗体则抑制其粘附性。可溶性多肽可抑制细胞对固定化TSP1多肽的黏附或在完整TSP1上的铺展，但在相同浓度下不能抑制细胞对IV型胶原或纤维连接蛋白的黏附或铺展，用ALA残基取代TSP1多肽中的几个残基使其在溶液中的抑制活性消失或减弱，但只有Arg-198取代才能完全失活固定化多肽的黏附活性。作为可溶性抑制物的必需残基是Asn-196、Val-197和Arg-198，但侧翼残基通过改变活性序列的构象或通过与整合素相互作用来增强该核心序列的抑制活性，该功能序列在所有已知的哺乳动物TSP1序列中都是保守的，在非洲爪哇的TSP1中，TSP1肽还抑制MDA-MB-435细胞与层粘连蛋白-L肽GD6的黏附，GD6含有潜在的整合素识别序列Asn-Leu-Arg，它来自于五肽模块中的类似位置。使用重组TSP1片段的粘附性研究也定位了该区域175-242残基与包含活性序列的β1整合素依赖的粘附性。
A synthetic peptide containing amino acid residues 190-201 of thrombospondin-l (TSP1) promoted adhesion of MDA-MB-435 breast carcinoma cells when immobilized and inhibited adhesion of the same cells to TSP1 when added in solution. Adhesion to this peptide was enhanced by a beta(1) integrin-activating antibody, Mn2+, and insulin-like growth factor I and was inhibited by an alpha(3)beta(1) integrin function-blocking antibody. The soluble peptide inhibited adhesion of cells to the immobilized TSP1 peptide or spreading on intact TSP1 but at the same concentrations did not inhibit attachment or spreading on type Iv collagen or fibronectin, Substitution of several residues in the TSP1 peptide with Ala residues abolished or diminished the inhibitory activity of the peptide in solution, but only substitution of Arg-198 completely inactivated the adhesive activity of the immobilized peptide. The essential residues for activity of the peptide as a soluble inhibitor are Asn-196, Val-197, and Arg-198, but flanking residues enhance the inhibitory activity of this core sequence, either by altering the conformation of the active sequence or by interacting with the integrin, This functional sequence is conserved in all known mammalian TSP1 sequences and in TSP1 from Xenopus laevis, The TSP1 peptide also inhibited adhesion of MDA-MB-435 cells to the laminin-l peptide GD6, which contains a potential integrin-recognition sequence Asn-Leu-Arg and is derived from a similar position in a pentraxin module. Adhesion studies using recombinant TSP1 fragments also localized beta 1 integrin-dependent adhesion to residues 175-242 of this region, which contain the active sequence.