Extracellular Membrane-proximal Domain of HAb18G/CD147 Binds to Metal Ion-dependent Adhesion Site (MIDAS) Motif of Integrin β1 to Modulate Malignant Properties of Hepatoma Cells
Extracellular Membrane-proximal Domain of HAb18G/CD147 Binds to Metal Ion-dependent Adhesion Site (MIDAS) Motif of Integrin β1 to Modulate Malignant Properties of Hepatoma Cells
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DOI：
10.1074/jbc.m111.277699
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发表时间：
2012-02-10
影响因子：
4.8
通讯作者：
Jiang, Jian-Li
中科院分区：
文献类型：
--
作者：
Li, Yong;Wu, Jiao;Jiang, Jian-Li
一些证据表明，HAb18G/CD147与整合素变异体α3β1和α6β1相互作用。然而，这种相互作用的机制在很大程度上仍不清楚。本研究采用哺乳动物蛋白质相互作用陷阱技术(MAPPIT)研究了CD147-整合素β1亚单位之间的相互作用。小发夹RNA干扰人肝细胞癌CD147的表达。采用裸鼠移植瘤模型和肝癌转移模型检测CD147在肿瘤发生和转移中的作用。我们发现HAb18G/CD147的胞外膜近端结构域(I型结构域)结合在整合素β1亚基的βA结构域的金属离子依赖的粘连部位，而HAb18G/CD147的I型结构域中的Asp(179)在相互作用中起着重要的作用。作用于整合素下游的粘着斑激酶(FAK)和磷酸化FAK的蛋白水平降低，HAb18G/CD147缺失导致肝癌细胞骨架结构重排。同时，肿瘤的迁移和侵袭能力、基质金属蛋白酶的分泌、体外集落形成率、体内肿瘤生长和转移潜能均降低。这些结果表明，HAb18G/CD147胞外I型结构域与整合素β1金属离子依赖的黏附位点基序相互作用激活了下游的FAK信号通路，从而增强了肝癌细胞的恶性特性。
Several lines of evidence suggest that HAb18G/CD147 interacts with the integrin variants alpha 3 beta 1 and alpha 6 beta 1. However, the mechanism of the interaction remains largely unknown. In this study, mammalian protein-protein interaction trap (MAPPIT), a mammalian two-hybrid method, was used to study the CD147-integrin beta 1 subunit interaction. CD147 in human hepatocellular carcinoma (HCC) cells was interfered with by small hairpin RNA. Nude mouse xenograft model and metastatic model of HCC were used to detect the role of CD147 in carcinogenesis and metastasis. We found that the extracellular membrane-proximal domain of HAb18G/CD147 (I-type domain) binds at the metal ion-dependent adhesion site in the beta A domain of the integrin beta 1 subunit, and Asp(179) in the I-type domain of HAb18G/CD147 plays an important role in the interaction. The levels of the proteins that act downstream of integrin, including focal adhesion kinase (FAK) and phospho-FAK, were decreased, and the cytoskeletal structures of HCC cells were rearranged bearing the HAb18G/CD147 deletion. Simultaneously, the migration and invasion capacities, secretion of matrix metalloproteinases, colony formation rate in vitro, and tumor growth and metastatic potential in vivo were decreased. These results indicate that the interaction of HAb18G/CD147 extracellular I-type domain with the integrin beta 1 metal ion-dependent adhesion site motif activates the downstream FAK signaling pathway, subsequently enhancing the malignant properties of HCC cells.