Cross-class inhibition of the cysteine proteinases cathepsins K, L, and S by the serpin squamous cell carcinoma antigen 1:: A kinetic analysis
Cross-class inhibition of the cysteine proteinases cathepsins K, L, and S by the serpin squamous cell carcinoma antigen 1:: A kinetic analysis
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DOI：
10.1021/bi972521d
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发表时间：
1998-04-14
期刊：
影响因子：
2.9
通讯作者：
Silverman, GA
中科院分区：
文献类型：
--
作者：
Schick, C;Pemberton, PA;Silverman, GA
人鳞状细胞癌抗原（SCCA）1和2是串联排列的基因，编码两种高分子量丝氨酸蛋白酶抑制剂（serpins）。虽然这些蛋白质是92%相同的，但它们的反应位点环的差异表明它们抑制不同类型的蛋白酶。我们以前的研究表明，SCCA 2抑制胰凝乳蛋白酶样丝氨酸蛋白酶[Schick等人（1997）J.Biol.Chem.272，1849-1855]。我们现在表明，与SCCA 2不同，SCCA 1对任何更常见类型的丝氨酸蛋白酶缺乏抑制活性，但却是原型溶酶体半胱氨酸蛋白酶组织蛋白酶K、L和S的有效跨类抑制剂。动力学分析表明，SCCA 1与组织蛋白酶K、L和S以1：1的化学计量相互作用，二级速率常数大于或等于1 × 10（5）M-1 s（-1）。这些速率常数与用原型生理半胱氨酸蛋白酶抑制剂胱抑素C获得的速率常数相当。同样相对于胱抑素C，SCCA 1是一种更有效的组织蛋白酶K介导的弹性蛋白溶解活性的抑制剂，通过形成更长寿命的底物-蛋白酶复合物。SCCA 1-组织蛋白酶S复合物的t（1/2）>1155 min，而半胱氨酸蛋白酶抑制剂C-组织蛋白酶复合物的反应时间为55 min。反应位点环的Gly和Ser残基之间的切割以及通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳检测到稳定的SCCA 1-组织蛋白酶S复合物表明，丝氨酸蛋白酶抑制剂与半胱氨酸蛋白酶的相互作用方式类似于典型的丝氨酸蛋白酶抑制剂。丝氨酸蛋白酶相互作用这些数据表明，取决于其反应位点环序列，哺乳动物丝氨酸蛋白酶抑制剂，在一般情况下，利用其动态的三级结构，从一个以上的机械类和SCCA 1，特别是，可能涉及一种新的抑制途径，旨在调节一个强大的阵列的溶酶体半胱氨酸蛋白酶的陷阱蛋白酶。
The human squamous cell carcinoma antigens (SCCA) 1 and 2 are tandemly arrayed genes that encode two high-molecular-weight serine proteinase inhibitors (serpins). Although these proteins are 92% identical, differences in their reactive site loops suggest that they inhibit different types of proteinases. Our previous studies show that SCCA2 inhibits chymotrypsin-like serine proteinases [Schick et al. (1997) J. Biol. Chem. 272, 1849-1855]. We now show that, unlike SCCA2, SCCA1 lacks inhibitory activity against any of the more common types of serine proteinases but is a potent cross-class inhibitor of the archetypal lysosomal cysteine proteinases cathepsins K, L, and S. Kinetic analysis revealed that SCCA1 interacted with cathepsins K, L, and S at 1:1 stoichiometry and with second-order rate constants greater than or equal to 1 x 10(5) M-1 s(-1). These rate constants were comparable to those obtained with the prototypical physiological cysteine proteinase inhibitor, cystatin C. Also relative to cystatin C, SCCA1 was a more potent inhibitor of cathepsin K-mediated elastolytic activity by forming longer lived inhibitor-proteinase complexes. The t(1/2) of SCCA1-cathepsin S complexes was >1155 min, whereas that of cystatin C-cathepsin complexes was 55 min. Cleavage between the Gly and Ser residues of the reactive site loop and detection of a stable SCCA1-cathepsin S complex by sodium dodecyl sulfate-polyacrylamide gel electrophoresis suggested that the serpin interacted with the cysteine proteinase in a manner similar to that observed for typical serpin-serine proteinase interactions. These data suggest that, contingent upon their reactive site loop sequences, mammalian serpins, in general, utilize their dynamic tertiary structure to trap proteinases from more than one mechanistic class and that SCCA1, in particular, may be involved in a novel inhibitory pathway aimed at regulating a powerful array of lysosomal cysteine proteinases.