Control of
            <i>Staphylococcus aureus</i>
            Quorum Sensing by a Membrane-Embedded Peptidase

Cosgriff, Chance J.; White, Chelsea R.; Teoh, Wei Ping; Grayczyk, James P.; Alonzo, Francis

doi:10.1128/iai.00019-19

Cited by 29 publications

(44 citation statements)

References 96 publications

(150 reference statements)

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“…Many bacteria encode multiple CPBPs, with S. aureus NCTC8325 containing at least six other CPBP enzymes in addition to LnsB ( 62 ). Of these, MroQ is a suspected protease that processes auto-inducing peptide ( 63 , 64 ). There is phenotypic evidence for roles of four other staphylococcal CPBPs in maintaining cell envelope integrity ( 65 ) and in the expression of cell wall-attached surface proteins with YSIRK peptide signals ( 66 ).…”

Section: Discussionmentioning

confidence: 99%

Lipoprotein N -Acylation in Staphylococcus aureus Is Catalyzed by a Two-Component Acyl Transferase System

Gardiner

Komazin

Matsuo

et al. 2020

mBio

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Bacterial lipoproteins (Lpps) are a class of membrane-associated proteins universally distributed among all bacteria. A characteristic N-terminal cysteine residue that is variably acylated anchors C-terminal globular domains to the extracellular surface, where they serve numerous roles, including in the capture and transport of essential nutrients. Lpps are also ligands for the Toll-like receptor 2 (TLR2) family, a key component of the innate immune system tasked with bacterial recognition. While Lpp function is conserved in all prokaryotes, structural heterogeneity in the N-terminal acylation state is widespread among Firmicutes and can differ between otherwise closely related species. In this study, we identify a novel two-gene system that directs the synthesis of N-acylated Lpps in the commensal and opportunistic pathogen subset of staphylococci. The two genes, which we have named the lipoprotein N-acylation transferase system (Lns), bear no resemblance to previously characterized N-terminal Lpp tailoring enzymes. LnsA (SAOUHSC_00822) is an NlpC/P60 superfamily enzyme, whereas LnsB (SAOHSC_02761) has remote homology to the CAAX protease and bacteriocin-processing enzyme (CPBP) family. Both LnsA and LnsB are together necessary and alone sufficient for N-acylation in Staphylococcus aureus and convert the Lpp chemotype from diacyl to triacyl when heterologously expressed in Listeria monocytogenes. Acquisition of lnsAB decreases TLR2-mediated detection of S. aureus by nearly 10-fold and shifts the activated TLR2 complex from TLR2/6 to TLR2/1. LnsAB thus has a dual role in attenuating TLR2 signaling in addition to a broader role in bacterial cell envelope physiology. IMPORTANCE Although it has long been known that S. aureus forms triacylated Lpps, a lack of homologs to known N-acylation genes found in Gram-negative bacteria has until now precluded identification of the genes responsible for this Lpp modification. Here, we demonstrate N-terminal Lpp acylation and chemotype conversion to the tri-acylated state is directed by a unique acyl transferase system encoded by two noncontiguous staphylococci genes (lnsAB). Since triacylated Lpps stimulate TLR2 more weakly than their diacylated counterparts, Lpp N-acylation is an important TLR2 immunoevasion factor for determining tolerance or nontolerance in niches such as in the skin microbiota. The discovery of the LnsAB system expands the known diversity of Lpp biosynthesis pathways and acyl transfer biochemistry in bacteria, advances our understanding of Lpp structural heterogeneity, and helps differentiate commensal and noncommensal microbiota.

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Section: Discussionmentioning

confidence: 99%

Lipoprotein N -Acylation in Staphylococcus aureus Is Catalyzed by a Two-Component Acyl Transferase System

Gardiner

Komazin

Matsuo

et al. 2020

mBio

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“…Murine infection models. Murine skin and soft tissue and systemic infections were performed as previously described with WT, ΔlipL mutant, and ΔlipLϩlipL (ATG-1) mutant strains (3,62).…”

Section: Methodsmentioning

confidence: 99%

Dynamic Relay of Protein-Bound Lipoic Acid in Staphylococcus aureus

et al. 2019

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Staphylococcus aureus competes for myriad essential nutrients during host infection. One of these nutrients is the organosulfur compound lipoic acid, a cofactor required for the activity of several metabolic enzyme complexes. In S. aureus, these include the E2 subunits of three α-ketoacid dehydrogenases and two H proteins, GcvH of the glycine cleavage system and its paralog, GcvH-L. We previously determined that the S. aureus amidotransferase LipL is required for lipoylation of the E2 subunits of pyruvate dehydrogenase (PDH) and branched-chain 2-oxoacid dehydrogenase (BCODH) complexes. The results from this study, coupled with those from Bacillus subtilis, suggested that LipL catalyzes lipoyl transfer from H proteins to E2 subunits. However, to date, the range of LipL targets, the extent of LipL-dependent lipoic acid shuttling between lipoyl domain-containing proteins, and the importance of lipoyl relay in pathogenesis remain unknown. Here, we demonstrate that LipL uses both lipoyl-H proteins as the substrates for lipoyl transfer to all E2 subunits. Moreover, LipL facilitates lipoyl relay between E2 subunits and between H proteins, a property that potentially constitutes an adaptive response to nutrient scarcity in the host, as LipL is required for virulence during infection. Together, these observations support a role for LipL in facilitating flexible lipoyl relay between proteins and highlight the complexity of protein lipoylation in S. aureus. IMPORTANCE Protein lipoylation is a posttranslational modification that is evolutionarily conserved from bacteria to humans. Lipoic acid modifications are found on five proteins in S. aureus, four of which are components of major metabolic enzymes. In some bacteria, the amidotransferase LipL is critical for the attachment of lipoic acid to these proteins, and yet it is unclear to what extent LipL facilitates the transfer of this cofactor. We find that S. aureus LipL flexibly shuttles lipoic acid among metabolic enzyme subunits, alluding to a dynamic redistribution mechanism within the bacterial cell. This discovery exemplifies a potential means by which bacteria optimize the use of scarce nutrients when resources are limited.

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“…More recently, it has been suggested that LyrA interacts with the histidine kinases of 10 two-component systems of S. aureus, including WalK, which is involved in controlling cell wall metabolism, leading to the suggestion that LyrA is a global regulator of two-component system activity (18). Another S. aureus CAAX protease, MroQ, was reported to be a regulator of the Agr quorum sensing system, potentially via interaction with AgrC histidine kinase (27,28). The related CAAX protease homologue from group B streptococcus, Abx1, has been shown to interact with and regulate the two-component system CovRS (17).…”

Section: Discussionmentioning

confidence: 99%

Regulated Cleavage of Glycan Strands by the Murein Hydrolase SagB in Staphylococcus aureus Involves a Direct Interaction with LyrA (SpdC)

2021

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LyrA (SpdC), a homologue of eukaryotic CAAX proteases that act on prenylated substrates, has been implicated in the assembly of several pathways of the envelope of Staphylococcus aureus. We described earlier the Lysostaphin resistance (Lyr) and Staphylococcal protein A display (Spd) phenotypes associated with loss of the lyrA (spdC) gene. However, a direct contribution to the assembly of pentaglycine crossbridges, the target of lysostaphin cleavage in S. aureus peptidoglycan, or of Staphylococcal protein A attachment to peptidoglycan could not be attributed directly to LyrA (SpdC). These two processes are catalyzed by the Fem factors and Sortase A, respectively. To gain insight into the function of LyrA (SpdC), here we use affinity chromatography and LC-MS/MS analysis and report that LyrA interacts with SagB. SagB cleaves glycan strands of peptidoglycan to achieve physiological length. Similar to sagB peptidoglycan, lyrA peptidoglycan contains extended glycan strands. Purified lyrA peptidoglycan can still be cleaved to physiological length by SagB in vitro. LyrA does not modify or cleave peptidoglycan, it also does not modify or stabilize SagB. The membrane bound domain of LyrA is sufficient to support SagB activity but predicted ‘CAAX enzyme’ catalytic residues in this domain are dispensable. We speculate that LyrA exerts its effect on bacterial prenyl substrates, specifically undecaprenol-bound peptidoglycan substrates of SagB, to help control glycan length. Such an activity also explains the Lyr and Spd phenotypes observed earlier. IMPORTANCE Peptidoglycan is assembled on the trans side of the plasma membrane from lipid II precursors into glycan chains that are crosslinked at stem peptides. In S. aureus, SagB, a membrane-associated N-acetylglucosaminidase, cleaves polymerized glycan chains to their physiological length. Deletion of sagB is associated with longer glycan strands in peptidoglycan, altered protein trafficking and secretion in the envelope, and aberrant excretion of cytosolic proteins. It is not clear whether SagB, with its single transmembrane segment, serves as the molecular ruler of glycan chains or whether other factors modulate its activity. Here, we show that LyrA (SpdC), a protein of the CAAX type II prenyl endopeptidase family, modulates SagB activity via interaction though its transmembrane domain.

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Control of Staphylococcus aureus Quorum Sensing by a Membrane-Embedded Peptidase

Cited by 29 publications

References 96 publications

Lipoprotein N -Acylation in Staphylococcus aureus Is Catalyzed by a Two-Component Acyl Transferase System

Lipoprotein N -Acylation in Staphylococcus aureus Is Catalyzed by a Two-Component Acyl Transferase System

Dynamic Relay of Protein-Bound Lipoic Acid in Staphylococcus aureus

Regulated Cleavage of Glycan Strands by the Murein Hydrolase SagB in Staphylococcus aureus Involves a Direct Interaction with LyrA (SpdC)

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