A cellular disintegrin and metalloproteinase (ADAM) is a new family of genes with structural homology to the snake venom metalloproteinases and disintegrins. We screened genes which were selectively expressed in the cachexigenic colon 26 adenocarcinoma subline in vivo. It was found that one novel cDNA clone, identified as a cachexigenic tumor selective gene, encodes a cysteinerich protein which shows a sequence similarity to that of both the snake venom metalloproteinases and thrombospondins. We named this cDNA clone A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-1). ADAMTS1 consists of six domains, 1) a proand 2) a metalloproteinase, 3) a disintegrin-like, 4) a thrombospondin (TSP) homologous domain containing TSP type I motif, 5) a spacer region, and 6) COOH-terminal TSP submotifs. Unlike other ADAMs, ADAMTS-1 does not possess a transmembrane domain and is a putative secretory protein. Therefore, ADAMTS-1 is a new type of ADAM family protein with TSP type I motifs. We demonstrated that the TSP homologous domain containing the TSP type I motif of ADAMTS-1 is functional for binding to heparin. ADAMTS-1 mRNA could be induced by stimulating colon 26 cells with an inflammatory cytokine, interleukin-1, in vitro. Moreover, intravenous administration of lipopolysaccharide in mice selectively induced ADAMTS-1 mRNA in kidney and heart. These data suggest that ADAM-TS-1 may be a gene whose expression is associated with various inflammatory processes as well as development of cancer cachexia.

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Cellular disintegrin and metalloproteinases (ADAMs) are a family of genes with a sequence similar to those of snake venom metalloproteinases and disintegrins. The ADAMTS-1 gene encodes a new type of ADAM protein with respect to possessing the thrombospondin (TSP) type I motifs. Expression of the gene is induced in kidney and heart by in vivo administration of lipopolysaccharide, suggesting a possible role in the inflammatory reaction. In this study, we characterized the ADAMTS-1 gene product by using a transient expression system in COS-7 cells. We found that the precursor and processed forms of ADAMTS-1 were secreted from cells. Under normal growth conditions, little or none of both forms was detected in the cell culture medium, and instead the majority was found associated with the extracellular matrix (ECM). In addition, when cells were cultured in the presence of heparin, the mature form of ADAMTS-1 protein was detected in the cell culture medium, suggesting that binding of ADAMTS-1 to the ECM is mediated through sulfated glycosaminoglycans such as heparan sulfate. Analyses of deletion mutants of the ADAMTS-1 protein revealed that the spacer region as well as three TSP type I motifs in the carboxyl-terminal region of the ADAMTS-1 protein are important for a tight interaction with the ECM. These results suggest that the ADAMTS-1 is a unique ADAM family protein that anchors at the ECM. Disintegrin and metalloproteinases (ADAMs)1 represent a new family of gene products that show significant sequence similarity to snake venom metalloproteinase and disintegrin (1, 2). So far, 18 -20 ADAM genes, including fertilin, epididymal apical protein I, cyritestin, meltrin, metalloproteinase-like/ disintegrin-like/cysteine-rich (MDC) protein, macrophage cellsurface antigen MS2, and metargidin, have been identified (3-8). Typical ADAMs are cell surface proteins that consist of a pro-, a metalloprotease-like, a disintegrin-like, a cysteine-rich, an epidermal growth factor-like, a transmembrane, and a cytoplasmic domain. Fertilin, the first ADAM described, has been implicated in integrin-mediated sperm-egg binding (3, 9); meltrin has been shown to be required for myotube formation (6). They are thought to function in cell-cell interaction. However, a recently cloned gene encoding tumor necrosis factor ␣ (TNF-␣)-converting enzyme (TACE) has been shown to be a membrane type metalloproteinase that also belongs to the ADAM family (10, 11). In Drosophila, an ADAM family gene, Kuzbanian has been demonstrated to play a role in the lateral inhibition during neurogenesis by cleavage of the extracellular domain of the transmembrane receptor Notch (12, 13). These observations indicate that some ADAMs, possessing a zinc binding motif, function by processing cell surface proteins. Interestingly, it has been found that mammalian disintegrinmetalloprotease (MADM or ADAM10) is also able to process pro-TNF-␣ (14, 15), whereas other ADAM members, MS2 and decysin, were identified as monocytic and dendritic cell-specific genes, respectively (7, 1...

A disintegrin-like and metalloproteinase with thrombospondin type I motifs-1 (ADAMTS-1) is an extracellular matrix-anchored metalloproteinase. In this study we have demonstrated that ADAMTS-1 is able to cleave a major cartilage proteoglycan, aggrecan. N-terminal sequencing analysis of the cleavage product revealed that ADAMTS-1 cleaves the Glu 1871^L eu 1872 bond within the chondroitin sulfate attachment domain of aggrecan. In addition, deletional analysis demonstrated that the C-terminal spacer region of ADAMTS-1 is necessary to degrade aggrecan. These results suggest that ADAMTS-1 may be involved in the turnover of aggrecan in vivo. ß

Cellular disintegrin and metalloproteinases (ADAMs) are a family of genes with a sequence similar to the snake venom metalloproteinases and disintegrins. AD-AMTS-1 is a unique ADAM family protein with respect to the presence of thrombospondin type I motifs and the capacity to bind to the extracellular matrix. Because ADAMTS-1 has a potential zinc-binding motif in the metalloproteinase domain, we examined in this study whether ADAMTS-1 is an active metalloproteinase by means of the proteinase trapping mechanism of ␣ 2 -macroglobulin. We found that the soluble type of ADAMTS-1 protein is able to form a covalent-binding complex with ␣ 2 -macroglobulin. Furthermore, the point mutation within the zinc-binding motif of ADAMTS-1 protein eliminates its capacity to bind to ␣ 2 -macroglobulin. These data demonstrate that the metalloproteinase domain of ADAMTS-1 is catalytically active. In addition, we showed that the removal of the pro-domain from the ADAMTS-1 precursor is impaired in the furin-deficient cell line, LoVo, and that the processing ability of the cells is restored by the co-expression of the furin cDNA. These data provide evidence that the ADAMTS-1 precursor is processed in vivo by furin endopeptidase in the secretory pathway. Consequently, ADAMTS-1 is an active metalloprotease that is associated with the extracellular matrix. This study strongly suggests that AD-AMTS-1 may play a role in the inflammatory process through its protease activity. Disintegrin and metalloproteinases (ADAMs)

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To clarify the role of disintegrin-like and metalloproteinase with thrombospondin type I motifs-1 (ADAMTS-1) in ovarian function, we examined abnormalities in ovulatory processes, folliculogenesis and the vascular system of ADAMTS-1 null ovaries. First, when immature female mice were treated with pregnant mare serum gonadotropin (PMSG)/human chorionic gonadotropin (hCG), the number of ovulated oocytes was markedly decreased in ADAMTS-1 null mice in comparision to ADAMTS-1 (+/-) controls. The proportion of anovulated follicles to total mature follicles was significantly higher in ADAMTS-1 null females when compared with controls. The numbers of growing follicles at each stage were counted. The number of follicles at type 5b (late preantral) and later stages was markedly reduced in ADAMTS-1 null mice, irrespective of gonadotropin treatment (no gonadotropins, PMSG alone or PMSG/hCG). These data demonstrate that impairment of ovarian function to ovulate oocytes in ADAMTS-1 null mice occurs at two different levels: in the development of growing follicles and ovulatory processes. Furthermore, ADAMTS-1 null ovaries included a number of unusual atretic follicles that showed no sign of oocyte degeneration but lost the surrounding granulosa cell layers and were considered to be derived from type 4 or 5a follicles. These results suggest that ADAMTS-1 is important for follicular development beyond the type 4 and/or 5a and for maintaining normal granulosa cell layers in follicles. Finally, the number of large blood vessels in the medullar zone was significantly decreased in ADAMTS-1 null mice ovaries, suggesting that ADAMTS-1 is also involved in the organization of the medullary vascular network.

Interleukin-1 (IL-1) exerts pleiotropic effects on a variety of tissues through binding to its receptor. Two distinct types of receptors for IL-1 have been characterized in mouse and human. Most of the IL-1 signal has been shown to be transmitted through type I IL-1R (80 kDa) in T lymphocytes as well as B lymphocytes and monocytes. Type II receptor may act as a suppressor of IL-1 biological activities by competing in binding with type I receptors on the cell surface. Functional studies of the type I IL-1R demonstrated that the cytoplasmic segments, possessing a sequence similarity with the Drosophila Toll gene product or IL-6R beta chain, gp130, are important for transmitting activity that induces cytokine genes. In the past three years, several groups reported that IL-1 and tumor necrosis factor (TNF) rapidly induce sphingomyelin turnover in various types of cells, producing ceramide, which may act as a second messenger molecule in an intracellular signaling cascade. Activation of both acid and neutral sphingomyelinases (SMases) has been suggested, and Schutz et al. proposed that the phosphatidylcholine-phospholipase C/acid SMase pathway is involved in TNF-induced NF-kappa B activation. However, our recent study showed that the NF-kappa B activation is induced by IL-1/TNF in fibroblasts from patients with type A Niemann-Pick disease, with acid SMase deficiency. This finding implies that acid SMase activity is not essential for the activation of NF-kappa B by IL-1/TNF at least in fibroblasts. Other signaling pathways including neutral SMase and unidentified protein kinases may be important for NF-kappa B-mediated cytokine gene activation.