Biological Role of ADAMTS Proteases

说明书(申请人提供)：ADAMTS蛋白酶具有重要的功能，如加工前胶原(ADAMTS-2、-3和-14)、大聚集蛋白多糖(ADAMTS-4、-5、-1)和von Willebrand因子(ADAMTS-13)，并在皮损、关节炎、脑瘤侵袭和特发性血小板减少性紫癜等疾病中发挥相应作用。然而，大多数ADAMTS酶的生物学功能尚不清楚。ADAMTS-9和ADAMTS-20是我们发现的两种酶，是所有ADAMTS酶中最大的。它们有一个独特的结构域结构，类似于线虫Gon-1酶，在性腺形态发生过程中对细胞迁移是必不可少的。目前已知ADAMTS-20在神经脊细胞迁移中起作用，但ADAMTS-9的功能尚不清楚。初步研究表明，在小鼠发育过程中，ADAMTS-9在中胚层及其衍生物中具有独特的时空表达模式。我们发现这是第一个定位于细胞表面的家族成员，尽管它没有跨膜结构域。此外，ADAMTS-9转基因细胞在软骨聚集素中可以切割出与ADAMTS-4相似的位置，提示ADAMTS-9是一种细胞表面聚集聚糖酶。我们报告ADAMTS-9存在于类风湿滑膜中。这些发现导致了一种假设，即ADAMTS-9对聚集素以及相关的蛋白多糖(如verscan和brevican)的蛋白分解对于完成正常发育以及关节炎等疾病至关重要。ADAMTS-9的辅助结构域可能在底物识别和靶向细胞表面方面发挥重要作用。其具体目的是确定ADAMTS-9的生理功能，表征其对聚集素和其他底物的活性，并确定这种活性和细胞表面定位的基础。在这样做的过程中，我们预计将比较ADAMTS-9和ADAMTS-20，以及其他相关的ADAMTS酶。这些目标将通过产生ADAMTS-9缺失小鼠、结构-功能分析以及潜在底物的生化和原位分析来实现。这些研究的意义在于提高了对发育过程中蛋白质分解和人类疾病，特别是关节炎的基本了解。

DESCRIPTION (provided by applicant): ADAMTS proteases have important functions such as processing of procollagen (ADAMTS-2, -3 and -14), large aggregating proteoglycans (ADAMTS-4, -5, -1), and von Willebrand factor (ADAMTS-13), with corresponding roles in disorders such as dermatosparaxis, arthritis, brain tumor invasion and idiopathic thrombocytopenic purpura. However, the biological function of most ADAMTS proteases is not known. ADAMTS-9 and ADAMTS-20, two enzymes we have discovered, are the largest of all ADAMTS enzymes. They have a unique domain structure similar to that of the C.elegans GON-1 enzyme that is essential for cell migration during gonadal morphogenesis. ADAMTS-20 is now known to have a role in neural crest cell migration, but the function of ADAMTS-9 is not known. Preliminary studies show that ADAMTS-9 has a unique temporal and spatial expression pattern in mesoderm and its derivatives during mouse development. We have found that this is the first family member to be localized to the cell surface, although it does not have a transmembrane domain. Furthermore, ADAMTS-9 transfected cells can cut a similar site in cartilage aggrecan as ADAMTS-4, suggesting that ADAMTS-9 is a cell surface aggrecanase. We report that ADAMTS-9 is present in rheumatoid synovium. These findings lead to the hypothesis that proteolysis of aggrecan, and related proteoglycans such as versican and brevican, by ADAMTS-9 is crucial to completion of normal development, as well as to diseases such as arthritis. The ancillary domains of ADAMTS-9 may play a substantial role in substrate recognition and targeting to the cell surface. The Specific Aims are to determine the physiological function of ADAMTS-9, characterize its activity against aggrecan and other substrates, and to determine the basis for such activity and for cell surface localization. In doing so, we anticipate comparing ADAMTS-9 to ADAMTS-20, as well as other relevant ADAMTS enzymes. These aims will be addressed by generation of ADAMTS-9 null mice, structure-function analysis, and analysis of potential substrates biochemically and in situ. The significance of these studies lies in improved fundamental understanding of proteolysis during development and human disease, especially arthritis.