The type II transmembrane serine proteases TMPRSS2 and HAT activate influenza viruses and the SARS - coronavirus ( TMPRSS2 ) in cell culture
However , it is at present largely unclear to what extent these proteases are expressed in viral target cells in human tissues .
The type II transmembrane serine proteases TMPRSS2 and HAT activate influenza viruses and the SARS - coronavirus ( TMPRSS2 ) in cell culture and may play an important role in viral spread and pathogenesis in the infected host .
However , it is at present largely unclear to what extent these proteases are expressed in viral target cells in human tissues .