2009-08-012024-05-16https://scholars.lib.ntu.edu.tw/handle/123456789/667395摘要：許多的報導都認為integrin β4 和 FAK蛋白都扮演重要的角色於腫瘤進程中。事實上，它們在細胞訊息與功能的角色具有相當密切的相似性與相關性，因而被建議這兩種蛋白可以共同的調控細胞內一些特定的訊息傳遞，進而促進腫瘤細胞的轉移。在此前題之下，我們發現FAK蛋白可以直接的與integrin β4結合。而此一交互作用乃是經由FAK蛋白的N端區域。這個發現也促使我們提出進一步的鑑認出此一交互作用最基本的氨基酸序列。基於這些鑑認出的氨基酸，同時，我們也將製造一個新的FAK突變株，其失去了與integrin β4結合的能力，以利進一步的在細胞功能與訊息傳遞上的探討研究。首先，利用這種FAK突變株我們將測試其對腫瘤細胞的入侵與附著的影響和對細胞生長與凋亡的改變。除此之外，在integrin β4專一性的活化條件下，FAK所引發的訊息傳遞也將被探討。從這些研究所得到的結果，不僅可直接的證實FAK在腫瘤演化進程的功能與角色，並可提供於乳癌轉移的治療應用。<br> Abstract: A number of studies indicated that both of β4integrin and FAK play an important role in tumor progression. In fact, their signaling and functions in tumor cells are similar and intimately associated, thereby suggesting that they may coordinately modulate certain specific cell signal pathways in the regulation of various tumor functions, particularly tumor metastasis. In agreement with this possibility, we have demonstrated that FAK indeed physically binds to β4 integrin through its amino-acid region in vivo and in vitro. At first, in combination with our previous studies, we therefore hypothesized that the activation of FAK by β4 integrin may occur by alternations of the intramolecular interaction between FAK’s FERM domain and its kinase domain, an autoinhibitory mechanism for FAK as described in our previous report. To reveal this, we will conduct a crystallographic study of this possibility by resolving the protein structure of activated complexes for the cytodomain of β4 integrin and the FAK’s FERM domain. Furthermore, these findings prompt us to further investigate how the complexes of β4 integrin-FAK contribute to tumor progression. To dissect the molecular mechanism of this novel signal complex, we then propose to identify the key motif/amino-acids responsible for β4 integrin binding on FAK, and which will allow us to generate FAK mutant(s) with deficiency on β4 integrin binding. We will employ this FAK mutant to further pursue relative functions and signaling downstream in a β4 integrin-FAK dependent manner. Subsequently, effects of integrin-FAK complexes on tumor invasion and adhesion as well as cell proliferation or apoptosis will be speculated and compared. Our efforts will also focus on the MAPK and PI3-kinase pathways to elucidate how their activities take place and collaborate with FAK in tumorigenesis and metastasis downstream of β4 integrin. At last, the complications of β4 integrin interacting and activating FAK will be confirmed using clinical tumor samples. Collectively, these studies will not only highlight a direct role for FAK as a key mediator downstream of integrins in tumor progression, also shed a light on the therapeutic applications in many cancers, including breast cancer.β4 integrinFAK訊息傳遞癌化轉移β4 integrinFAKsignal transductiontumorigenesismetastasis