Roles of CUB and LDL receptor class A domain repeats of a transmembrane serine protease matriptase in its zymogen activation
Roles of CUB and LDL receptor class A domain repeats of a transmembrane serine protease matriptase in its zymogen activation
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DOI：
10.1093/jb/mvs118
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发表时间：
2013-01-01
影响因子：
2.7
通讯作者：
Fushiki, Tohru
中科院分区：
文献类型：
--
作者：
Inouye, Kuniyo;Tomoishi, Marie;Fushiki, Tohru
基质酶是一种II型跨膜丝氨酸蛋白酶，含有2个补体蛋白酶C1r/ c1s -海胆胚胎生长因子-骨形态发生蛋白结构域（CUB重复）和4个低密度脂蛋白受体a类结构域（LDLRA重复）。基质酶的单链酶原已被发现表现出大量的蛋白酶活性，可能引起其自身的激活（即转化为二硫连接的双链完全活性形式），尽管激活似乎主要由双链分子介导。我们的目的是评估CUB和LDLRA重复序列在酶原激活中的作用。重组基质酶可溶性截断构建体在COS-1细胞中的瞬时表达研究表明，CUB重复序列对酶原激活具有抑制作用，可能是因为它促进了双链分子与基质酶抑制剂肝细胞生长因子激活因子抑制剂1型的相互作用。相反，LDLRA重复序列对酶原激活有促进作用。LDLRA重复序列的作用似乎反映了它增加酶原活性的能力。含有LDLRA重复序列的假酶原重组基质酶的蛋白水解活性高于不含重复序列的假酶原。我们的发现为这些非催化结构域在活性基质酶生成中的作用提供了新的见解。
Matriptase is a type II transmembrane serine protease containing two complement proteases C1r/C1s-urchin embryonic growth factor-bone morphogenetic protein domains (CUB repeat) and four low-density lipoprotein receptor class A domains (LDLRA repeat). The single-chain zymogen of matriptase has been found to exhibit substantial protease activity, possibly causing its own activation (i.e. conversion to a disulfide-linked two-chain fully active form), although the activation seems to be mediated predominantly by two-chain molecules. Our aim was to assess the roles of CUB and LDLRA repeats in zymogen activation. Transient expression studies of soluble truncated constructs of recombinant matriptase in COS-1 cells showed that the CUB repeat had an inhibitory effect on zymogen activation, possibly because it facilitated the interaction of two-chain molecules with a matriptase inhibitor, hepatocyte growth factor activator inhibitor type-1. By contrast, the LDLRA repeat had a promoting effect on zymogen activation. The effect of the LDLRA repeat seems to reflect its ability to increase zymogen activity. The proteolytic activities were higher in pseudozymogen forms of recombinant matriptase containing the LDLRA repeat than in a pseudozymogen without the repeat. Our findings provide new insights into the roles of these non-catalytic domains in the generation of active matriptase.