Activation of matriptase zymogen

Matriptase is a type II transmembrane serine protease expressed abundantly in the epithelial cells and keratinocyte. It plays a key role in the establishment and maintenance of epithelial integrity. Matriptase is considered to be at the most upstream in cellular protease cascade. Activation of its zymogen is the most critical step in regulation of downstream proteases activities and physiological functions. It has recently found that the exposure of matriptase-expressing epithelial cells and its homogenate to mildly acidic pH induces the rapid activation of matriptase zymogen. On the other hand, high ionic strength prevents this activation. The activation of the zymogen is thought to be triggered by the acidification and the lowering of ionic strength in cell-surface microenvironments.