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An intramembrane sensory circuit monitors sortase A-mediated processing of streptococcal adhesins. Sci Signal 2019 May 07;12(580)

Date

05/09/2019

Pubmed ID

31064885

Pubmed Central ID

PMC6662179

DOI

10.1126/scisignal.aas9941

Scopus ID

2-s2.0-85065780047 (requires institutional sign-in at Scopus site)   15 Citations

Abstract

Bacterial adhesins mediate adhesion to substrates and biofilm formation. Adhesins of the LPXTG family are posttranslationally processed by the cell membrane-localized peptidase sortase A, which cleaves the LPXTG motif. This generates a short C-terminal peptide (C-pep) that remains in the cell membrane, whereas the mature adhesin is incorporated into the cell wall. Genes encoding adhesins of the oral bacterium Streptococcus gordonii were differentially expressed depending on whether the bacteria were isolated from saliva or dental plaque and appeared to be coordinately regulated. Deletion of sspA and sspB (sspAB), both of which encode LPXTG-containing adhesins, unexpectedly enhanced adhesion and biofilm formation. C-peps produced from a model LPXTG-containing adhesin localized to the cell membrane and bound to and inhibited the intramembrane sensor histidine kinase SGO_1180, thus preventing activation of the cognate response regulator SGO_1181. The absence of SspAB C-peps induced the expression of the scaCBA operon encoding the lipoprotein adhesin ScaA, which was sufficient to preserve and even enhance biofilm formation. This C-pep-driven regulatory circuit also exists in pathogenic streptococci and is likely conserved among Gram-positive bacteria. This quality control mechanism ensures that the bacteria can form biofilms under diverse environmental conditions and may play a role in optimizing adhesion and biofilm formation.

Author List

Hall JW, Lima BP, Herbomel GG, Gopinath T, McDonald L, Shyne MT, Lee JK, Kreth J, Ross KF, Veglia G, Herzberg MC

Author

Gopinath Tata PhD Assistant Professor in the Biophysics department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Adhesins, Bacterial
Amino Acid Motifs
Amino Acid Sequence
Aminoacyltransferases
Bacterial Proteins
Biofilms
Cysteine Endopeptidases
Dental Plaque
Gene Expression Regulation, Bacterial
Membrane Glycoproteins
Mutation
Peptide Fragments
Saliva
Sequence Homology, Amino Acid
Streptococcus gordonii