Mycobacterium tuberculosis MycP1 protease plays a dual role in regulation of ESX-1 secretion and virulence.
Mycobacterium tuberculosis uses the ESX-1 secretion system to deliver virulence proteins during infection of host cells. Here we report a mechanism of posttranscriptional control of ESX-1 mediated by MycP1, a M. tuberculosis serine protease. We show that MycP1 is required for ESX-1 secretion but that, unexpectedly, genetic inactivation of MycP1 protease activity increases secretion of ESX-1 substrates. We demonstrate that EspB, an ESX-1 substrate required for secretion, is a target of MycP1 in vitro and in vivo. During macrophage infection, an inactive MycP1 protease mutant causes hyperactivation of ESX-1-stimulated innate signaling pathways. MycP1 is required for growth in mice during acute infection, while loss of its protease activity leads to attenuated virulence during chronic infection. As the key ESX-1 substrates ESAT-6 and CFP-10 are highly immunogenic, fine-tuning of their secretion by MycP1 may balance virulence and immune detection and be essential for successful maintenance of long-term M. tuberculosis infection.
Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA.
Yamini M
YM
Ohol
David H
DH
Goetz
Kaman
K
Chan
Michael U
MU
Shiloh
Charles S
CS
Craik
Jeffery S
JS
Cox
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D015169:Colony Count, Microbial; D055786:Gene Knockout Techniques; D008099:Liver / Q000382:microbiology; D008168:Lung / Q000473:pathology; D008264:Macrophages / Q000382:microbiology; D026901:Membrane Transport Proteins / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008954:Models, Biological; D009169:Mycobacterium tuberculosis / Q000378:metabolism* / Q000472:pathogenicity*; D011499:Protein Processing, Post-Translational; D013154:Spleen / Q000382:microbiology; D013381:Subtilisins / Q000235:genetics / Q000502:physiology*; D016019:Survival Analysis; D037521:Virulence Factors / Q000378:metabolism*
D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D037521:Virulence Factors; D013381:Subtilisins; C471626:mycosin-1, Mycobacterium tuberculosis