The integrin co-activator Kindlin-3 is expressed and functional in a non-hematopoietic cell, the endothelial cell.
The integrin co-activator Kindlin-3 is expressed and functional in a non-hematopoietic cell, the endothelial cell.
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DOI：
10.1074/jbc.m109.085746
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发表时间：
2010-06-11
期刊：
影响因子：
--
通讯作者：
Plow EF
中科院分区：
文献类型：
--
作者：
Bialkowska K;Ma YQ;Bledzka K;Sossey-Alaoui K;Izem L;Zhang X;Malinin N;Qin J;Byzova T;Plow EF
整合素活化对于许多细胞反应是至关重要的，包括细胞粘附、迁移和存活。最近在小鼠中的研究特别强调了kindlin-3在整合素活化中的重要作用。人类中的Kindlin-3缺乏症现在也有记录，包括出血、频繁感染和骨硬化症的症状，这些症状是无法激活β1、β2和β3整联蛋白的结果。迄今为止，kindlin-3被认为仅限于造血细胞。在这篇文章中，我们证明了kindlin-3存在于来自各种解剖学来源的人内皮细胞中。RT-PCR和Western blot检测内皮细胞中KINDLIN-3的mRNA和蛋白。当通过质谱法进行测序时，该蛋白被鉴定为真实的Kindlin-3，并且明确地与KINDLIN-1和KINDLIN-2或任何其他已知蛋白区分开。通过定量真实的时间PCR，kindlin-3在内皮细胞中的水平是kindlin-2的水平的20-50%。使用敲低的方法，我们表明，kindlin-3在整合素介导的内皮细胞粘附中发挥作用。该功能取决于整合素和底物，并且与kindlin-2的功能不同。基质胶中管状结构的形成也受到kindlin-3敲低的损害。从机制上讲，kindlin的独特功能可以追溯到它们在含整合素的粘附结构中的亚细胞定位的差异。因此，现在必须修改个别kindlin以细胞类型特异性方式发挥其功能的流行观点，以考虑相同细胞类型内不同家族成员的不同功能。
Integrin activation is crucial for numerous cellular responses, including cell adhesion, migration, and survival. Recent studies in mice have specifically emphasized the vital role of kindlin-3 in integrin activation. Kindlin-3 deficiency in humans also has now been documented and includes symptoms of bleeding, frequent infections, and osteopetrosis, which are consequences of an inability to activate β1, β2, and β3 integrins. To date, kindlin-3 was thought to be restricted to hematopoietic cells. In this article, we demonstrate that kindlin-3 is present in human endothelial cells derived from various anatomical origins. The mRNA and protein for KINDLIN-3 was detected in endothelial cells by reverse transcription-PCR and Western blots. When subjected to sequencing by mass spectrometry, the protein was identified as authentic kindlin-3 and unequivocally distinguished from KINDLIN-1 and KINDLIN-2 or any other known protein. By quantitative real time PCR, the level of kindlin-3 in endothelial cells was 20–50% of that of kindlin-2. Using knockdown approaches, we show that kindlin-3 plays a role in integrin-mediated adhesion of endothelial cells. This function depends upon the integrin and substrate and is distinct from that of kindlin-2. Formation of tube-like structures in Matrigel also was impaired by kindlin-3 knockdown. Mechanistically, the distinct functions of the kindlins can be traced to differences in their subcellular localization in integrin-containing adhesion structures. Thus, the prevailing view that individual kindlins exert their functions in a cell type-specific manner must now be modified to consider distinct functions of the different family members within the same cell type.