Wang Wei-Man, Lee Seungbok, Steiglitz Barry M, Scott Ian C, Lebares Carter C, Allen M Leah, Brenner Mitchell C, Takahara Kazuhiko, Greenspan Daniel S
Department of Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
J Biol Chem. 2003 May 23;278(21):19549-57. doi: 10.1074/jbc.M300767200. Epub 2003 Mar 19.
The metalloproteinase ADAMTS-2 has procollagen I N-proteinase activity capable of cleaving procollagens I and II N-propeptides in vitro, whereas mutations in the ADAMTS-2 gene in dermatosparaxis and Ehlers-Danlos syndrome VIIC show this enzyme to be responsible in vivo for most biosynthetic processing of procollagen I N-propeptides in skin. Yet despite its important role in the regulation of collagen deposition, information regarding regulation and substrate specificity of ADAMTS-2 has remained sparse. Here we demonstrate that ADAMTS-2 can, like the procollagen C-proteinases, be regulated by transforming growth factor-beta 1 (TGF-beta 1), with implications for mechanisms whereby this growth factor effects net increases in formation of extracellular matrix. TGF-beta 1 induced ADAMTS-2 mRNA approximately 8-fold in MG-63 osteosarcoma cells in a dose- and time-dependent, cycloheximide-inhibitable manner, which appeared to operate at the transcriptional level. Secreted ADAMTS-2 protein induced by TGF-beta 1 was 132 kDa and was identical in size to the fully processed, active form of the protease. Biosynthetic processing of ADAMTS-2 to yield the 132-kDa form is shown to be a two-step process involving sequential cleavage by furin-like convertases at two sites. Surprisingly, purified recombinant ADAMTS-2 is shown to cleave procollagen III N-propeptides as effectively as those of procollagens I and II, whereas processing of procollagen III is shown to be decreased in Ehlers-Danlos VIIC. Thus, the dogma that procollagen I and procollagen III N-proteinase activities are provided by separate enzymes appears to be false, whereas the phenotypes of dermatosparaxis and Ehlers-Danlos VIIC may arise from defects in both type I and type III collagen biosynthesis.
金属蛋白酶ADAMTS - 2具有前胶原I N - 蛋白酶活性，能够在体外切割前胶原I和II的N - 前肽，而皮肤松弛症和埃勒斯 - 当洛综合征VIIC中ADAMTS - 2基因的突变表明，该酶在体内负责皮肤中前胶原I N - 前肽的大部分生物合成加工。然而，尽管其在胶原蛋白沉积调节中起重要作用，但关于ADAMTS - 2的调节和底物特异性的信息仍然很少。在这里，我们证明ADAMTS - 2可以像前胶原C - 蛋白酶一样，受转化生长因子 - β1（TGF - β1）调节，这对该生长因子影响细胞外基质形成净增加的机制具有重要意义。TGF - β1以剂量和时间依赖性、环己酰亚胺可抑制的方式在MG - 63骨肉瘤细胞中诱导ADAMTS - 2 mRNA增加约8倍，这似乎在转录水平起作用。TGF - β1诱导分泌的ADAMTS - 2蛋白为132 kDa，大小与完全加工的活性蛋白酶形式相同。ADAMTS - 2生物合成加工产生132 kDa形式是一个两步过程，涉及在两个位点被弗林蛋白酶样转化酶顺序切割。令人惊讶地是，纯化的重组ADAMTS - 2切割前胶原III N - 前肽的效果与前胶原I和II的N - 前肽一样有效，而在埃勒斯 - 当洛VIIC中前胶原III的加工减少。因此，认为前胶原I和前胶原III N - 蛋白酶活性由不同酶提供的教条似乎是错误的，而皮肤松弛症和埃勒斯 - 当洛VIIC的表型可能源于I型和III型胶原蛋白生物合成的缺陷。
