Signaling Through Membrane Type 1 Matrix Metalloproteinase

描述（由申请人提供）：膜型1基质金属蛋白酶（MT1-MMP）是一种跨膜蛋白酶，具有胞外蛋白水解结构域和短细胞质尾。基质金属蛋白酶-2 （TIMP-2）组织抑制剂对MT1-MMP的蛋白水解活性有生理抑制作用。TIMP-2与MT1-MMP结合，该复合物通过蛋白酶胞质尾部介导的内吞作用内化。我们广泛的初步工作表明，TIMP-2与MT1-MMP的结合迅速诱导ERK1/2 MAP激酶激活，从而上调细胞增殖和迁移。这些作用需要细胞质尾部而不是MT1 -MMP的蛋白水解活性。

DESCRIPTION (provided by applicant): Membrane-type 1 matrix metalloproteinase (MT1-MMP) is a transmembrane proteinase with an extracellular proteolytic domain and a short cytoplasmic tail. The proteolytic activity of MT1-MMP is inhibited physiologically by tissue inhibitor of matrix metalloproteinase-2 (TIMP-2). TIMP-2 binds to MT1-MMP and the complex is internalized by endocytosis mediated by the cytoplasmic tail of the proteinase. Our extensive preliminary work has shown that binding of TIMP-2 to MT1-MMP rapidly induces ERK1/2 MAP kinase activation, which upregulates cell proliferation and migration. These effects require the cytoplasmic tail but not the proteolytic activity of MT1 -MMP. We therefore propose to: 1. Determine the physiologic significance of ERK1/2 activation generated by TIMP-2 binding to MT1-MMP. For this purpose, wild-type and MT1-MMP knockout mouse embryonic fibroblasts will be used to determine if this signaling mechanism and its resulting biological effects are active in stromal cells expressing physiologic amounts of MT1 -MMP and dependent on the cytoplasmic tail but not the proteolytic activity of the proteinase. 2. Investigate the molecular mechanism of intracellular signaling by MT1-MMP. We propose to identify proteins that interact with the cytoplasmic tail of MT1-MMP upon TIMP-2 addition, and to characterize the role of endocytosis of the TIMP-2-MT1-MMP complex in the control of MT1-MMP-mediated intracellular signaling. The results of the proposed research project will elucidate novel mechanisms through which interactions among cell surface proteins generate intracellular signaling that has important roles in the regulation of numerous cell functions. A detailed understanding of these mechanisms can therefore have relevant implications for our comprehension of a variety of physiological and pathological processes, and for the development of pharmacological tools aimed to control them.