Evidence for the occurrence of membrane-type serine protease 1/matriptase on the basolateral sides of enterocytes.
Evidence for the occurrence of membrane-type serine protease 1/matriptase on the basolateral sides of enterocytes.
复制标题
DOI：
10.1042/bj20041639
复制
发表时间：
2005-06
期刊：
影响因子：
--
通讯作者：
S. Tsuzuki;N. Murai;Yuka Miyake;K. Inouye;Hirofumi Hirayasu;T. Iwanaga;T. Fushiki
中科院分区：
文献类型：
--
作者：
S. Tsuzuki;N. Murai;Yuka Miyake;K. Inouye;Hirofumi Hirayasu;T. Iwanaga;T. Fushiki
MT-SP1（膜型丝氨酸蛋白酶1）/基质酶是一种上皮源性整体膜酶。本研究的目的是检测该酶是否存在于正常成年动物的肠细胞等单柱状上皮细胞的基底外侧。用大鼠MT-SP1/基质酶表达质粒瞬时转染COS-1猴肾细胞，我们发现该酶在翻译后被Gly149和Ser150切割，部分c端部分（Ser150- val855）通过与NTF （n端片段）（Met1-Gly149）结合留在细胞中。而其他部分则释放到培养基中，并且通过与肝细胞生长因子激活因子抑制剂1型共表达而激活释放增加。对大鼠空肠制备的粗膜进行Western-blot分析显示存在NTF，但可忽略或不存在该蛋白的c端部分。Percoll超离心对粗膜进行分离，然后进行Western-blot分析，发现NTF的分离谱与E-cadherin的分离谱显著相关，E-cadherin是侧膜上的一种粘附分子。空肠免疫染色显示NTF出现在外侧膜上，但未出现在根尖膜上。这些结果表明，相当多的MT-SP1/基质酶分子出现在正常上皮细胞的基底外侧，并支持了我们的假设，即该酶可能的生理功能是通过调节细胞-细胞和/或细胞-基质粘附来控制上皮细胞的更新。
MT-SP1 (membrane-type serine protease 1)/matriptase is an epithelial-derived integral membrane enzyme. The purpose of the present study was to examine whether the enzyme exists on the basolateral side of simple columnar epithelial cells, such as enterocytes, of normal adult animals. Using COS-1 monkey kidney cells transiently transfected with rat MT-SP1/matriptase expression plasmids, we found that the enzyme is post-translationally processed by the cleavage between Gly149 and Ser150, that a portion of the C-terminal part (Ser150-Val855) remains in the cells by association with the NTF (N-terminal fragment) (Met1-Gly149), while the other portions are released into the medium and that the release is increased on activation by co-expression with hepatocyte growth factor activator inhibitor type-1. Western-blot analysis of crude membranes prepared from rat jejunum demonstrated the presence of the NTF but negligible or no occurrence of the C-terminal part of the protein. Fractionation of the crude membranes by ultracentrifugation with Percoll followed by Western-blot analysis showed that the fractionation profile of the NTF correlated significantly with that of E-cadherin, an adhesion molecule on the lateral membrane. Immunostaining of the jejunum demonstrated the occurrence of the NTF on the lateral membranes but not on the apical membranes. These results suggest that considerable MT-SP1/matriptase molecules occur on the basolateral sides of normal epithelial cells and support our hypothesis that a possible physiological function of this enzyme is the control of epithelial-cell turnover by regulating cell-cell and/or cell-substratum adhesions.