SIGNAL TRANSDUCTION BY INTEGRINS - INCREASED PROTEIN TYROSINE PHOSPHORYLATION CAUSED BY CLUSTERING OF BETA-1 INTEGRINS
SIGNAL TRANSDUCTION BY INTEGRINS - INCREASED PROTEIN TYROSINE PHOSPHORYLATION CAUSED BY CLUSTERING OF BETA-1 INTEGRINS
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DOI：
10.1073/pnas.88.19.8392
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发表时间：
1991-10-01
影响因子：
11.1
通讯作者：
JULIANO, RL
中科院分区：
文献类型：
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作者：
KORNBERG, LJ;EARP, HS;JULIANO, RL
细胞粘附受体的整合素家族介导细胞与细胞外基质之间的许多相互作用。 由于细胞外基质对细胞行为有着深远的影响，因此整联蛋白似乎可以跨越细胞膜传递生化信号。 到目前为止，这些假定信号的性质仍然难以捉摸。 使用抗体介导的整联蛋白受体的聚集来模拟粘附接触形成期间发生的整联蛋白聚集过程。 将人表皮癌（KB）细胞与抗β-1整联蛋白单克隆抗体在冰上孵育30分钟，然后在37 ℃下用抗大鼠IgG诱导。 这种治疗，诱导整联蛋白聚集，刺激酪氨酸残基的115- 130-kDa的蛋白质复合物称为pp 130的磷酸化。 当整联蛋白聚集在磷酸酶抑制剂原钒酸钠的存在下，pp 130表现出磷酸化的大幅增加相比，其中整联蛋白聚集在不存在钒酸盐的情况下。 在不存在钒酸盐的情况下，在整合素聚集开始后10-20分钟或在其存在下5-10分钟后观察到最大pp 130磷酸化。 这些时间进程大致平行的形成整合素簇细胞表面上观察到的荧光显微镜。 pp 130磷酸化依赖于存在的抗整联蛋白抗体的量。 此外，pp 130的酪氨酸磷酸化显示出特异性，因为它被整合素α-3和β-1亚基的抗体刺激，但不被其他整合素α亚基或非整合素细胞表面蛋白的抗体刺激。 免疫沉淀实验清楚地表明pp 130本身不是β-1整联蛋白。 因此，据推测，整合素刺激的酪氨酸磷酸化的pp 130可能反映了细胞外基质和细胞内部之间的重要信号转导过程的一部分。
The integrin family of cell adhesion receptors mediates many of the interactions between cells and the extracellular matrix. Because the extracellular matrix has profound influences on cell behavior, it seems likely that integrins transduce biochemical signals across the cell membrane. The nature of these putative signals has, thus far, remained elusive. Antibody-mediated clustering of integrin receptors was used to mimic the integrin clustering process that occurs during formation of adhesive contacts. Human epidermal carcinoma (KB) cells were incubated with an anti-beta-1 integrin monoclonal antibody for 30 min on ice followed by indubation at 37-degrees-C with anti-rat IgG. This treatment, which induced integrin clustering, stimulated the phosphorylation on tyrosine residues of a 115- to 130-kDa complex of proteins termed pp130. When integrins were clustered in the presence of the phosphatase inhibitor sodium orthovanadate, pp130 showed a substantial increase in phosphorylation compared to the case in which integrins were clustered in the absence of vanadate. Maximal pp130 phosphorylation was observed 10-20 min after initiation of integrin clustering in the absence of vanadate or after 5-10 min in its presence. These time courses roughly parallel the formation of integrin clusters on the cell surface as observed by fluorescence microscopy. pp130 phosphorylation depended on the amount of anti-integrin antibody present. Additionally, the tyrosine phosphorylation of pp130 showed specificity since it was stimulated by antibodies to the integrin alpha-3 and beta-1 subunits but not by antibodies to other integrin alpha subunits or to nonintegrin cell surface proteins. Immunoprecipitation experiments clearly demonstrated that pp130 is not itself a beta-1 integrin. It is postulated, therefore, that the integrin-stimulated tyrosine phosphorylation of pp130 may reflect part of an important signal transduction process between the extracellular matrix and the cell interior.