Cochaperone Interactions in Export of the Type III Needle Component PscF of Pseudomonas Aeruginosa
Overview
Authors
Affiliations
Type III secretion (T3S) systems allow the export and translocation of bacterial effectors into the host cell cytoplasm. Secretion is accomplished by an 80-nm-long needle-like structure composed, in Pseudomonas aeruginosa, of the polymerized form of a 7-kDa protein, PscF. Two proteins, PscG and PscE, stabilize PscF within the bacterial cell before its export and polymerization. In this work we screened the 1,320-A(2) interface between the two chaperones, PscE and PscG, by site-directed mutagenesis and determined hot spot regions that are important for T3S function in vivo and complex formation in vitro. Three amino acids in PscE and five amino acids in PscG, found to be relevant for complex formation, map to the central part of the interacting surface. Stability assays on selected mutants performed both in vitro on purified PscE-PscG complexes and in vivo on P. aeruginosa revealed that PscE is a cochaperone that is essential for the stability of the main chaperone, PscG. Notably, when overexpressed from a bicistronic construct, PscG and PscF compensate for the absence of PscE in cytotoxic P. aeruginosa. These results show that all of the information needed for needle protein stabilization and folding, its presentation to the T3 secreton, and its export is present within the sequence of the PscG chaperone.
Diversity and structural-functional insights of alpha-solenoid proteins.
Arrias P, Osmanli Z, Peralta E, Chinestrad P, Monzon A, Tosatto S Protein Sci. 2024; 33(11):e5189.
PMID: 39465903 PMC: 11514114. DOI: 10.1002/pro.5189.
Beyond Antibiotics: What the Future Holds.
Benyamini P Antibiotics (Basel). 2024; 13(10).
PMID: 39452186 PMC: 11504868. DOI: 10.3390/antibiotics13100919.
Zeng Z, Liu L, Xiao S, Lu J, Liu Y, Li J mBio. 2022; 13(4):e0125022.
PMID: 35861543 PMC: 9426511. DOI: 10.1128/mbio.01250-22.
Lian L, Li W, Xue T, Ren J, Tang F, Liu Y Braz J Microbiol. 2021; 53(1):289-301.
PMID: 34652743 PMC: 8882520. DOI: 10.1007/s42770-021-00627-8.
Hotinger J, Pendergrass H, May A Biomolecules. 2021; 11(2).
PMID: 33669653 PMC: 7922566. DOI: 10.3390/biom11020316.