GELATINASE A/MT MMP SYSTEM IN CELL ADHESION AND MOTILITY

描述：（改编自研究者摘要）矩阵 真核细胞分泌的金属蛋白酶（MMPs）启动组织 通过降解现有ECM大分子如胶原蛋白 和蛋白聚糖。 恶性细胞利用这些蛋白酶促进肿瘤 侵袭和转移。 调查员对生物学的研究 MMPs的功能是基于这样的假设： 细胞外蛋白水解是通过细胞壁的区室化来完成的。 酶通过与细胞表面分子结构的相互作用 和/或ECM的原纤维，其中酶原的生理活化 发生。 因此，这种相互作用的机理研究是本领域的主要焦点。 调查员的注意。 在这方面，细胞表面的发现 明胶酶A（GeIA）的活化机理及其膜的分离 激活剂，一种整合的膜金属蛋白酶MT-MMP， 突破 GelA的调控C末端结构域（GelACTD）在细胞内起着重要的作用。 在细胞表面活化机制中起关键作用， 酶与整联蛋白的结合、抑制剂TIMP-2的结合和底物识别。 研究人员最近报道了这个结构域的晶体结构。 基于这个结构，研究者创造并描述了 一个包含60个单氨基酸取代突变体的文库， 暴露的残基。 利用这些突变体， 测定GelACTD的TIMP-2结合表面。 这些变种人将会 有助于进一步研究激活机制。 的 研究人员还发现，C-末端结构域直接与 催化结构域和这种相互作用严重影响的结合 酶对底物 根据这一观察，研究人员开发了 “反式”互补试验，其中酶由两个 独立表达的结构域，因此这种相互作用现在可以 研究了 最后，研究人员发现，GeIA膜激活剂 MT-MMP可被募集到粘连灶中。 因此MT-MMP的调节 跨胞吞区室和细胞表面之间的运输可能 在细胞粘附和运动中起关键作用。 该提案结合 生物化学，生物物理，细胞和分子生物学方法， 利用这些结果， 明胶酶和完整膜的胞外蛋白水解机制 蛋白酶在分子和细胞水平上。 详细了解 催化机制、细胞表面活化和 GelA/MT-MMP/TIMP-2系统在侵袭表型细胞中将作为一种新的表达系统进化。 这些研究的结果。

DESCRIPTION: (adapted from the investigator's abstract) Matrix Metalloproteases (MMPs) secreted by eucaryotic cells initiate tissue remodeling by degradation of existing ECM macromolecules such as collagens and proteoglycans. Malignant cells exploit these proteases to promote tumor invasion and metastasis. The investigator's research into biological function of MMPs is based on the hypothesis that spatially regulated extracellular proteolysis is accomplished by compartmentalization of the enzymes via their interaction with molecular structures on the cell surfaces and/or fibrils of the ECM where the physiological activation of proenzymes occurs. Thus mechanistic study of such interactions is a major focus of the investigator's attention. In this respect the discovery of a cell surface activation mechanism of Gelatinase A (GeIA) and isolation of its membrane activator, an integral membrane metalloprotease MT-MMP, were recent breakthroughs. The regulatory C-terminal domain of GelA (GelACTD) plays a pivotal role in the cell surface activation mechanism, interaction of the enzyme with integrin, binding of inhibitor TIMP-2 and substrate recognition. The investigator has recently reported the crystal structure of this domain. Now based on this structure, the investigator has created and characterized a library of 60 single amino-acid substitution mutants that span solvent exposed residues of this domain. Using these mutants the investigator determined TIMP-2 binding surface of GelACTD. These mutants will be instrumental in further investigation of the activation mechanism. The investigator also discovered that C-terminal domain directly interacts with catalytic domain and this interaction critically affects the binding of the enzyme to substrate. Based on this observation the investigator developed "in trans" complementation test where the enzyme is assembled from two independently expressed domains, so that this interaction can be now studied. Finally, the investigator discovered that GeIA membrane activator MT-MMP can be recruited into focal adhesions. Thus regulation of MT-MMP trafficking between transendocytic compartment and cell surface is likely to play a critical role in cell adhesion and motility. This proposal combining biochemical, biophysical, cell and molecular biology approaches is designed to capitalize on these results to advance the understanding of the mechanisms of extracellular proteolysis by gelatinases and integral membrane proteases on a molecular and cellular level. Detailed understanding of mechanisms of catalysis, cell surface activation and the role of GelA/MT-MMP/TIMP-2 system in invasive phenotype of cells will evolve as a result of these studies.