[Cover Caption]　

  Volume 2 Number 5   October 17, 2006

Matriptase is a type II transmembrane serine protease.  It is initially synthesized as a single-chain zymogen, and undergoes autoactivation to gain its proteolytic activity at “activation foci”.  HAI-1 is required to facilitate matriptase trafficking to activation foci; after activation, HAI-1 serves as a potent inhibitor for matriptase.   Through HAI-1, the matriptase activity is well regulated.  An imbalance between matriptase and HAI-1 levels results in abnormal matriptase activation, contributing to cancer development and malignant progression.  Matriptase-activated HGF or PAR-2 could promote tumor cell growth and survival through the c-Met receptor or the G-protein-coupled receptor signal pathway.  Furthermore, HGF induces cell mobility and coordinates with the matriptase-activated uPA/plasmin system to facilitate cancer cell invasion by degrading extracellular matrix.  

For more, please see the review paper ([PDF (1.2 MB)]) published in this issue.