tetano
Editor, Senior Moderator
J Biol Chem
. 2020 Jul 15;jbc.RA120.014525.
doi: 10.1074/jbc.RA120.014525. Online ahead of print.
Intracellular autoactivation of TMPRSS11A, an airway epithelial transmembrane serine protease
Ce Zhang[SUP] 1 [/SUP], Yikai Zhang[SUP] 1 [/SUP], Shengnan Zhang[SUP] 1 [/SUP], Zhiting Wang[SUP] 1 [/SUP], Shijin Sun[SUP] 1 [/SUP], Meng Liu[SUP] 1 [/SUP], Yue Chen[SUP] 1 [/SUP], Ningzheng Dong[SUP] 1 [/SUP], Qingyu Wu[SUP] 1 [/SUP]
Affiliations
Abstract
Type II transmembrane serine proteases (TTSPs) are a group of enzymes participating in diverse biological processes. Some members of the TTSP family are implicated in viral infection. TMPRSS11A is a TTSP expressed on the surface of airway epithelial cells, which has been shown to cleave and activate spike proteins of the severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome coronaviruses (CoVs). In this study, we examined the mechanism underlying the activation cleavage of TMPRSS11A that converts the one-chain zymogen to a two-chain enzyme. By expression in human embryonic kidney 293, esophageal EC9706 and lung epithelial A549 and 16HBE cells, western blotting, and site-directed mutagenesis, we found that the activation cleavage of human TMPRSS11A was mediated by autocatalysis. Moreover, we found that TMPRSS11A activation cleavage occurred before the protein reached the cell surface, as indicated by studies with trypsin digestion to remove cell surface proteins, treatment with cell organelle-disturbing agents to block intracellular protein trafficking, and analysis of a soluble form of TMPRSS11A without the transmembrane domain. We also showed that TMPRSS11A was able to cleave the SARS-CoV-2 spike protein. These results reveal an intracellular autocleavage mechanism in TMPRSS11A zymogen activation, which differs from the extracellular zymogen activation reported in other TTSPs. These findings provide new insights into the diverse mechanisms in regulating TTSP activation.
Keywords: TMPRSS11A; cell surface enzyme; protease; proteolytic enzyme; serine protease; transmembrane domain.
. 2020 Jul 15;jbc.RA120.014525.
doi: 10.1074/jbc.RA120.014525. Online ahead of print.
Intracellular autoactivation of TMPRSS11A, an airway epithelial transmembrane serine protease
Ce Zhang[SUP] 1 [/SUP], Yikai Zhang[SUP] 1 [/SUP], Shengnan Zhang[SUP] 1 [/SUP], Zhiting Wang[SUP] 1 [/SUP], Shijin Sun[SUP] 1 [/SUP], Meng Liu[SUP] 1 [/SUP], Yue Chen[SUP] 1 [/SUP], Ningzheng Dong[SUP] 1 [/SUP], Qingyu Wu[SUP] 1 [/SUP]
Affiliations
- PMID: 32675285
- DOI: 10.1074/jbc.RA120.014525
Abstract
Type II transmembrane serine proteases (TTSPs) are a group of enzymes participating in diverse biological processes. Some members of the TTSP family are implicated in viral infection. TMPRSS11A is a TTSP expressed on the surface of airway epithelial cells, which has been shown to cleave and activate spike proteins of the severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome coronaviruses (CoVs). In this study, we examined the mechanism underlying the activation cleavage of TMPRSS11A that converts the one-chain zymogen to a two-chain enzyme. By expression in human embryonic kidney 293, esophageal EC9706 and lung epithelial A549 and 16HBE cells, western blotting, and site-directed mutagenesis, we found that the activation cleavage of human TMPRSS11A was mediated by autocatalysis. Moreover, we found that TMPRSS11A activation cleavage occurred before the protein reached the cell surface, as indicated by studies with trypsin digestion to remove cell surface proteins, treatment with cell organelle-disturbing agents to block intracellular protein trafficking, and analysis of a soluble form of TMPRSS11A without the transmembrane domain. We also showed that TMPRSS11A was able to cleave the SARS-CoV-2 spike protein. These results reveal an intracellular autocleavage mechanism in TMPRSS11A zymogen activation, which differs from the extracellular zymogen activation reported in other TTSPs. These findings provide new insights into the diverse mechanisms in regulating TTSP activation.
Keywords: TMPRSS11A; cell surface enzyme; protease; proteolytic enzyme; serine protease; transmembrane domain.