Biological Role of ADAMTS Proteases

描述（由申请人提供）：ADAMTS蛋白酶具有重要的功能，如加工前胶原（ADAMTS-2、-3和-14）、大聚集蛋白聚糖（ADAMTS-4、-5、-1）和血管性血友病因子（ADAMTS-13），在疾病如皮肤麻痹、关节炎、脑肿瘤侵袭和特发性血小板减少性紫癜中具有相应的作用。然而，大多数ADAMTS蛋白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。它们具有类似于秀丽隐杆线虫GON-1酶的独特结构域结构，该结构域结构对于性腺形态发生期间的细胞迁移是必需的。目前已知ADAMTS-20在神经嵴细胞迁移中发挥作用，但ADAMTS-9的功能尚不清楚。初步研究表明，ADAMTS-9在小鼠发育过程中的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转染的细胞可以切割软骨聚集蛋白聚糖中与ADAMTS-4相似的位点，表明ADAMTS-9是细胞表面聚集蛋白聚糖酶。我们报告，ADAMTS-9是目前在类风湿性关节炎滑膜。这些发现导致了这样的假设，即ADAMTS-9对聚集蛋白聚糖和相关蛋白聚糖如多功能蛋白聚糖和短蛋白聚糖的蛋白水解对于完成正常发育以及疾病如关节炎至关重要。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。具体目的是确定ADAMTS-9的生理功能，表征其对聚集蛋白聚糖和其他底物的活性，并确定此类活性和细胞表面定位的基础。在此过程中，我们预计将ADAMTS-9与ADAMTS-20以及其他相关的ADAMTS酶进行比较。这些目标将通过生成ADAMTS-9裸小鼠，结构-功能分析，以及潜在底物的生化和原位分析来解决。这些研究的意义在于提高对发育和人类疾病（特别是关节炎）过程中蛋白质水解的基本理解。

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.