TY  - JOUR
AU  - Bunduc, Catalin
AU  - Ding, Y.
AU  - Kuijl, C.
AU  - Marlovits, Thomas
AU  - Bitter, W.
AU  - Houben, E. N. G.
TI  - Reconstitution of a minimal ESX-5 type VII secretion system suggests a role for PPE proteins in the outer membrane transport of proteins
JO  - mSphere
VL  - 8
IS  - 5
SN  - 2379-5042
CY  - Washington, DC
PB  - American Society for Microbiology
M1  - PUBDB-2024-00793
SP  - e00402-23
PY  - 2023
AB  - Mycobacteria utilize type VII secretion systems (T7SSs) to secrete proteins across their highly hydrophobic and diderm cell envelope. Pathogenic mycobacteria have up to five different T7SSs, called ESX-1 to ESX-5, which are crucial for growth and virulence. Here, we use a functionally reconstituted ESX-5 system in the avirulent species Mycobacterium smegmatis that lacks ESX-5, to define the role of each esx-5 gene in system functionality. By creating an array of gene deletions and assessing protein levels of components and membrane complex assembly, we observed that only the five components of the inner membrane complex are required for its assembly. However, in addition to these five core components, active secretion also depends on both the Esx and PE/PPE substrates. Tagging the PPE substrates followed by subcellular fractionation, surface labeling and membrane extraction showed that these proteins localize to the mycobacterial outer membrane. This indicates that they could play a role in secretion across this enigmatic outer barrier. These results provide the first full overview of the role of each esx-5 gene in T7SS functionality. 
LB  - PUB:(DE-HGF)16
C6  - pmid:37747201
UR  - <Go to ISI:>//WOS:001191361100020
DO  - DOI:10.1128/msphere.00402-23
UR  - https://bib-pubdb1.desy.de/record/603156
ER  -