Analysis of molecular mechanisms on integrin-family specific adhesion

整合素家族特异性粘附的分子机制分析

• 批准号: 12680694
• 负责人: KINASHI Tatsuo
• 金额: $ 2.37万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12680694/
• 关键词: integrin; LFA-1; cytoplasmic regions; Rap1; ICAM-1; PKC; PI3 kinase; endocytosis; 細胞運動; LFA-l; ICAM-l; Rap-1; PMA; 細胞接着; 細胞遊走

Leukocyte integrin LFA-1 plays a critical role in leukocyte migration and immunological synapse formation. In these processes, Rap1 are involved in avidity regulation of LFA-1 upon stimulation with chemokines and antigen. Avidity changes of integrins are regulated through their cytoplasmic regions. To identify specific residues that are involved in these processes, we have reconstituted human LFA-1 bearing truncated and point-mutated αL and β2 cytoplasmic regions and examined their effects on Rap1 -dependent adhesion to ICAM-1. Truncation of the αL, but not β2 subunit cytoplasmic region abolished Rap1 -dependent adhesion to ICAM-1. The two lysine residues (KK1097/1099) in the αL subunit were found to be critical in the Rap-1 dependent adhesion to ICAM-1. The KK1097/1099AA mutation was also defective in binding to ICAM-1 triggered by SDF-1. On the other hand, the substitution of tyrosine to alanine (Y735A) of the β2 subunit inhibited internalization of LFA-1, and impaired detachment, which resulted in elongated cell shape. Our findings have revealed the primary role of the αL cytoplasmic region in the response to the inside-out signaling of Rap1 and the β2 subunit in the subsequent post-adhesion events.

白细胞整合素LFA-1在白细胞迁移和免疫突触形成中起关键作用。在这些过程中，Rap1参与趋化因子和抗原刺激下LFA-1的活性调节。整合素的活性变化受其细胞质区调控。为了确定参与这些过程的特定残基，我们重建了人类LFA-1携带截断和点突变的αL和β2细胞质区域，并研究了它们对Rap1依赖的ICAM-1粘附的影响。截断αL而不截断β2亚基细胞质区域，可消除Rap1对ICAM-1的依赖性粘附。αL亚基上的两个赖氨酸残基（KK1097/1099）在Rap-1依赖于ICAM-1的粘附过程中起关键作用。KK1097/1099AA突变在与SDF-1触发的ICAM-1结合时也存在缺陷。另一方面，酪氨酸取代β2亚基的丙氨酸（Y735A）抑制了LFA-1的内化，破坏了脱离，导致细胞形状拉长。我们的研究结果揭示了αL细胞质区在Rap1和β2亚基在随后的粘附后事件中对Rap1和β2亚基的内向外信号反应中的主要作用。

项目成果

木梨達雄: "臨床免疫Vol34「インテグリンの接着性を制御する細胞内分子群」"科学評論社. 9 (2000)

Tatsuo Kinashi：“临床免疫学第34卷“控制整合素粘附的细胞内分子”” Kagaku Hyoronsha 9（2000）。

Suga, K: "CD98 induces LFA-1-mediated cell adhesion in lymphoid cells via activation of Rap1"FEBS Letters. 489. 249-253 (2001)

Suga, K：“CD98 通过激活 Rap1 诱导淋巴细胞中 LFA-1 介导的细胞粘附”FEBS Letters。

Tatsuo Kinashi: "Distinct Mechanisms of α_5β1 integin activation by Ha-Ras and R-Ras"Journal of Biological Chemistry. 275. 22590-22596 (2000)

Tatsuo Kinashi：“Ha-Ras 和 R-Ras 激活 α_5β1 整合素的独特机制”生物化学杂志 275. 22590-22596 (2000)。

Koko Katagiri: "Rap1 functions as a key regulator of T-cell and antigen-presenting cell interactions and modulates T-cell responses"Molecular and Cellular Biology. 22・4. 1001-1015 (2002)

Koko Katagiri：“Rap1 作为 T 细胞和抗原呈递细胞相互作用的关键调节因子并调节 T 细胞反应”《分子和细胞生物学》22·4 (2002)。

Koji Suga: "CD98 induces LFA-1-mediated cell adhesion in lymphoid cells via activation of Rap1"FEBS Letters. 489. 249-253 (2001)

Koji Suga：“CD98 通过激活 Rap1 诱导淋巴细胞中 LFA-1 介导的细胞粘附”FEBS Letters。