Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
Biochem Biophys Res Commun. 2010 Jun 11;396(4):927-32. doi: 10.1016/j.bbrc.2010.05.025. Epub 2010 May 9.
ADAM family proteins are type I transmembrane, zinc-dependent metalloproteases. This family has multiple conserved domains, including a signal peptide, a pro-domain, a metalloprotease domain, a disintegrin (DI) domain, a cysteine-rich (Cys) domain, an EGF-like domain, a transmembrane domain, and a cytoplasmic domain. The Cys and DI domains may play active roles in regulating proteolytic activity or substrate specificity. ADAM19 has an autolytic processing activity within its Cys domain, and the processing is necessary for its proteolytic activity. To identify a new physiological function of ADAM19, we screened for associating proteins by using the extracellular domain of ADAM19 in a yeast two-hybrid system. Cysteine-rich protein 2 (CRIP2) showed an association with ADAM19 through its DI and Cys domains. Sequence analysis revealed that CRIP2 is a secretable protein without a classical signal. CRIP2 secretion was increased by overexpression of ADAM19 and decreased by suppression of ADAM19 expression. Moreover, CRIP2 secretion increased in parallel with the autolytic processing of ADAM19 stimulated by lipopolysaccharide. These findings suggest that ADAM19 autolysis is activated by lipopolysaccharide and that ADAM19 promotes the secretion of CRIP2.
ADAM 家族蛋白是一种Ⅰ型跨膜、锌依赖性金属蛋白酶。该家族具有多个保守结构域，包括信号肽、前肽、金属蛋白酶结构域、解聚素（DI）结构域、富含半胱氨酸（Cys）结构域、EGF 样结构域、跨膜结构域和胞质结构域。Cys 和 DI 结构域可能在调节蛋白水解活性或底物特异性方面发挥积极作用。ADAM19 在其 Cys 结构域内具有自水解加工活性，该加工对于其蛋白水解活性是必需的。为了鉴定 ADAM19 的新生理功能，我们使用 ADAM19 的细胞外结构域在酵母双杂交系统中筛选相关蛋白。富含半胱氨酸蛋白 2（CRIP2）通过其 DI 和 Cys 结构域与 ADAM19 发生关联。序列分析表明，CRIP2 是一种没有经典信号的可分泌蛋白。ADAM19 的过表达增加了 CRIP2 的分泌，而 ADAM19 表达的抑制则降低了 CRIP2 的分泌。此外，CRIP2 的分泌随着脂多糖刺激的 ADAM19 自水解的增加而平行增加。这些发现表明，ADAM19 自水解被脂多糖激活，并且 ADAM19 促进了 CRIP2 的分泌。
