Integrin-linked kinase associated with integrin activation
Integrin-linked kinase associated with integrin activation
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DOI：
10.1182/blood-2008-07-169136
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发表时间：
2009-05-21
期刊：
影响因子：
20.3
通讯作者：
Miyata, Toshiyuki
中科院分区：
文献类型：
--
作者：
Honda, Shigenori;Shirotani-Ikejima, Hiroko;Miyata, Toshiyuki
血小板整合素α IIb β 3的活化受细胞内信号通路的严格控制，包括talin在内的几种分子已被鉴定为α IIb β 3活化的关键分子。然而，与α IIb β 3激活相关的整个途径仍有待确定。为了解决这个问题，我们建立了一个中国仓鼠卵巢细胞系（亲本细胞），表达组成型激活的嵌合整合素α IIb α 6 B β 3，然后通过全基因组诱变获得表达失活的α IIb α 6 B β 3的突变细胞。我们已经进行了表达克隆以分离负责突变细胞中整合素活化的信号分子。我们表明，整合素连接激酶（ILK）的突变体细胞中的整合素激活缺陷的补充。突变细胞中的ILK mRNA含有2个无义突变，R317 X和W383 X，处于复合杂合状态，导致ILK表达完全丧失。此外，突变体细胞显示内源性β 1整联蛋白的活化部分受损。亲代细胞中ILK的敲低显著抑制了α IIb α 6 B β 3的活化状态。然而，ILK的过度表达并没有拯救受损的整合素激活在塔林敲低的亲本细胞，而塔林-F3，塔林头域的一个子域的过度表达，恢复功能。我们目前的数据表明，ILK有助于由内而外的整合素激活。（血。2009; 113：5304-5313）
Platelet integrin alpha IIb beta 3 activation is tightly controlled by intracellular signaling pathways, and several molecules, including talin, have been identified as critical for alpha IIb beta 3 activation. However, the whole pathway associated with alpha IIb beta 3 activation remains to be determined. To address this issue, we established a Chinese hamster ovary cell line (parental cells) that expresses constitutively activated chimeric integrin alpha IIb alpha 6B beta 3, and then obtained mutant cells expressing inactivated alpha IIb alpha 6B beta 3 by genome-wide mutagenesis. We have performed expression cloning to isolate signaling molecules responsible for integrin activation in the mutant cells. We show that integrin-linked kinase (ILK) complements defective integrin activation in the mutant cells. ILK mRNAs in the mutant cells contained 2 nonsense mutations, R317X and W383X, in a compound heterozygous state, resulting in a complete loss of ILK expression. Moreover, the mutant cells showed partially impaired activation of endogenous beta 1 integrins. Knockdown of ILK in parental cells significantly suppressed the activated state of alpha IIb alpha 6B beta 3. However, ILK overexpression did not rescue the impaired integrin activation in talin knocked-down parental cells, whereas overexpression of talin-F3, a subdomain of the talin head domain, restored the function. Our present data suggest that ILK contributes to inside-out integrin activation. (Blood. 2009; 113: 5304-5313)