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oai:ir.soken.ac.jp:00001087 2023-06-20T14:48:19Z 2:430:22

Activation of Integrin-based Cell Adhesion inMouse L Fibroblasts Expressing Stabilized βCatenin in the Nucleus Activation of Integrin-based Cell Adhesion inMouse L Fibroblasts Expressing Stabilized βCatenin in the Nucleus 石原, 悟 イシハラ, サトル ISHIHARA, Satoru 総合研究大学院大学 博士（学術） β catenin is involved not only in the cadherin-based cell adhesion system but also in the Wnt signaling pathway. In this pathway, it is supposed that β catenin is phosphorylated by glycogen synthase kinase-3β(GSK-3β) to become susceptible to degradation, that the Wnt signaling suppresses GSK-3β to increase the amount of non-phosphorylated, stable β catenin, and that the stable β catenin affects the transcription of various genes in the nucleus. To separate the role of β catenin in intracellular signaling from its role in the cadherin-based cell adhesion, they constructed a mutant β catenin(mbH) with amino acid substitutions at its putative GSK-3β phosphorylation site (GSKP sequence), and introduced it into L fibroblasts that lack the cadherin expression. In stable transfectants (LmbH), not only mbH but also endogenous wild type β catenin was stabilized. Green fluorescence protein (GFP) carrying the mutated GSKP sequence also stabilized the endogenous β catenin in L cells, indicating that the mutated GSKP sequence suppresses the degradation machinery for β catenin. Furthermore, by adding the nuclear localization signal to mbH, they obtained L transfectants (LmbHN) expressing the stabilized β catenin predominantly in the nucleus. Under the long-term aggregation conditions, LmbHN formed compact cell aggregates consisting mainly of 2-5 cells. LmbH also showed a similar aggregation activity but to a lesser extent, and parent L cells mostly remained to be dissociated. Close analyses by immunofluorescence microscopy and the cell adhesion inhibition assay with RGD peptides revealed that aggregation activity is attributed to the integrin-based cell adhesion. Considering that the amount of stabilized β catenin in the nucleus is significantly larger in LmbHN than in LmbH, they speculate that the accumulation of β catenin in the nucleus resulted in the activation of integrin-based cell adhesion. The transfectants established in this study, thus, will provide an advantageous system to selectively analyze the role of β catenin in the nucleus and in the regulation of integrin activity. application/pdf 総研大甲第281号 thesis 1997-03-24 application/pdf application/pdf https://ir.soken.ac.jp/record/1087/files/甲281_要旨.pdf https://ir.soken.ac.jp/record/1087/files/甲281_本文.pdf https://ir.soken.ac.jp/records/1087 eng