A region in urokinase plasminogen receptor domain III controlling a functional association with α5β1 integrin and tumor growth
A region in urokinase plasminogen receptor domain III controlling a functional association with α5β1 integrin and tumor growth
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DOI：
10.1074/jbc.m512311200
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发表时间：
2006-05-26
影响因子：
4.8
通讯作者：
Ossowski, Liliana
中科院分区：
文献类型：
--
作者：
Chaurasia, Pratima;Aguirre-Ghiso, Julio A.;Ossowski, Liliana
高表达的尿激酶纤溶酶原激活物受体（uPAR）可与α 5 β 1整合素相互作用，导致持续的ERK激活和致瘤性。破坏这种相互作用会降低ERK活性，迫使癌细胞进入休眠状态。我们确定了一个网站在uPAR结构域III是不可或缺的这些影响。衍生自结构域III中的序列（残基240-248）的9-mer肽结合纯化的α 5 β 1整联蛋白。在该肽中或在全长可溶性uPAR中取代单个氨基酸（S245 A）会损害纯化的整联蛋白的结合。在最近解决的晶体结构的uPAR的Ser-245被限制在大的外表面的受体，一个位置，这是很好地从中央分离的尿激酶纤溶酶原结合腔。通过比较诱导表达uPAR（wt）或uPAR（S245 A）突变体的细胞，检查该位点对α 5 β 1整联蛋白依赖性细胞功能的影响。将uPARwt转染到具有低内源性uPAR水平、无活性整联蛋白、低ERK活性和体内休眠表型的细胞中可恢复这些功能并恢复体内生长。相反，用uPAR（S245 A）转染相同的细胞仅引起非常小的变化。高度恶性细胞与野生型而非S245 A突变肽的孵育破坏uPAR整合素相互作用，导致ERK活性下调。该结合位点和侧向uPAR-α 5 β 1整联蛋白相互作用与ERK途径活化和肿瘤生长的相关性暗示其为癌症治疗的可能特异性靶标。
Highly expressed urokinase plasminogen activator receptor (uPAR) can interact with alpha 5 beta 1 integrin leading to persistent ERK activation and tumorigenicity. Disrupting this interaction reduces ERK activity, forcing cancer cells into dormancy. We identified a site in uPAR domain III that is indispensable for these effects. A 9-mer peptide derived from a sequence in domain III ( residues 240-248) binds purified alpha 5 beta 1 integrin. Substituting a single amino acid ( S245A) in this peptide, or in full-length soluble uPAR, impairs binding of the purified integrin. In the recently solved crystal structure of uPAR the Ser-245 is confined to the large external surface of the receptor, a location that is well separated from the central urokinase plasminogen binding cavity. The impact of this site on alpha 5 beta 1 integrin-dependent cell functions was examined by comparing cells induced to express uPAR(wt) or the uPAR(S245A) mutant. Transfecting uPARwt into cells with low endogenous levels of uPAR, inactive integrin, lowERK activity, and a dormant phenotype in vivo restores these functions and reinstates growth in vivo. In contrast, transfection of the same cells with uPAR(S245A) elicits only very small changes. Incubation of highly malignant cells with the wild-type, but not the S245A mutant peptide, disrupts the uPAR integrin interaction leading to down-regulation of ERK activity. The relevance of this binding site, and of the lateral uPAR-alpha 5 beta 1 integrin interaction, to ERK pathway activation and tumor growth implicates it as a possible specific target for cancer therapy.