Potentiation of the ligand-binding activity of integrin α3β1 via association with tetraspanin CD151
Potentiation of the ligand-binding activity of integrin α3β1 via association with tetraspanin CD151
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DOI：
10.1073/pnas.0409493102
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发表时间：
2005-02-08
影响因子：
11.1
通讯作者：
Sekiguchi, K
中科院分区：
文献类型：
--
作者：
Nishiuchi, R;Sanzen, N;Sekiguchi, K
CD 151是四跨膜蛋白之一，与细胞表面主要的层粘连蛋白受体整合素001形成稳定的复合物。我们发现，通过筛选与整联蛋白α 3 β 1-CD 151复合物的反应性获得的抗CD 151 mAb 80能够从整联蛋白α 3 β 1解离CD 151，从而使我们能够从纯化的整联蛋白α 3 β 1-CD 151复合物中去除CD 151。由此获得的不含CD 151的整联蛋白α 3 β 1显示其与层粘连蛋白-10/11（整联蛋白α 3 β 1的高亲和力配体）结合的能力显著降低，同时其与识别活化的含β 1整联蛋白的mAb AG 89的反应性降低。这些结果提出了整合素α 3 β 1与CD 151的结合通过维持其活化构象而增强整合素的配体结合活性的可能性。为了支持这种可能性，当不含CD 151的整合素α 3 β 1与纯化的CD 151重新结合时，配体结合活性得以恢复。8 C3诱导的CD 151从整合素α 3 β 1的解离也通过荧光共振能量转移成像在活细胞表面上被证明，伴随着细胞粘附到层粘连蛋白-10/11包被的基底的减少。通过RNA干扰敲低CD 151也导致细胞粘附活性的降低。总之，这些结果表明，CD 151协会调节整合素α 3 β 1的配体结合活性，通过稳定其活化构象，不仅与纯化的蛋白质，而且在生理环境中。
CD151, one of the tetraspanins, forms a stable complex with integrin 001, the major laminin receptor on the cell surface. We found that 80, an anti-CD151 mAb obtained by screening for reactivity with integrin alpha3beta1-CD151 complexes, was capable of dissociating CD151 from integrin alpha3beta1, thereby allowing us to deplete CD151 from purified integrin alpha3beta1-CD151 complexes. The CD151-free integrin alpha3beta1 thus obtained showed a significant reduction in its ability to bind to laminin-10/11, a high-affinity ligand for integrin alpha3beta1, with a concomitant reduction in its reactivity with mAb AG89, which recognizes activated beta1-containing integrins. These results raised the possibility that the association of integrin alpha3beta1 with CD151 potentiates the ligand-binding activity of the integrin through sustaining its activated conformation. In support of this possibility, the ligand-binding activity was restored when CD151-free integrin alpha3beta1 was reassociated with purified CD151. 8C3-induced dissociation of CD151 from integrin alpha3beta1 was also demonstrated on the surface of living cells by fluorescent resonance energy transfer imaging, accompanied by a concomitant reduction in the cell adhesion to laminin-10/11-coated substrates. CD151 knock-down by RNA interference also resulted in a,eduction in the adhesive activity of the cells. Taken together, these results indicate that CD151 association modulates the ligand-binding activity of integrin alpha3beta1 through stabilizing its activated conformation not only with purified proteins but also in a physiological context.