Dataset Information

Phosphoproteomic analysis of Staphylococcus aureus

ABSTRACT: S. aureus is one of the major human pathogens that greatly impacts individuals and causes a variety of illnesses ranging from minor skin infections to life-threatening diseases, such as endocarditis, pneumonia, septicemia and toxic shock syndrome. Stk1/Stp1 are particular important for S. aureus pathogenesis and survival as they are thought to participate in regulating virulence, cell wall structure and antibiotic resistance. Understanding how Ser/Thr phosphorylation regulates virulence and antibiotic resistance will provide foundation for the development of novel therapeutic strategies against S. aureus infection. The phosphoproteomic analysis of Staphylococcus aureus Newman strain led to the identification of 76 peptides with mapped phosphorylation sites belonging to 29 distinct proteins. In the case of Stk1, only one peptide (residues 157-182), with the sequence ALSETSLTQTNHVLGTVQYFSPEQAK, was predicted to have a cluster of six phosphorylation sites (Ser159, Thr161, Ser162, Thr164, Thr166 and Thr172). This segment overlaps with the sequence of kinase activation loop (residues 154-176) in Stk1. Further biochemical studies revealed cis autophosphorylation of Thr172 in the GT/S motif is necessary for self-activation and kinase activity of Stk1, whereas the trans autophosphorylation of other activation loop serines/threonins are essential for the optimal kinase activity of Stk1.

INSTRUMENT(S): TripleTOF 5600

ORGANISM(S): Staphylococcus Aureus

SUBMITTER: Weihao Zheng

LAB HEAD: Zigang Li

PROVIDER: PXD006285 | Pride | 2018-10-24

REPOSITORIES: Pride

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			Action	DRS
	zwhNOphos20150615-0905.mgf	Mgf
	zwhNOphos20150615-0905.xml	Xml
	zwhNOphos20150615.wiff	Wiff

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Publications

Autophosphorylation Mechanism of the Ser/Thr Kinase Stk1 From Staphylococcus aureus.

Zheng Weihao W Cai Xiaodan X Li Shuiming S Li Zigang Z

Frontiers in microbiology 20180420

The eukaryotic-like Ser/Thr kinase Stk1 is crucial for virulence, cell wall biosynthesis, and drug susceptibility in methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA). Importantly, MRSA lacking Stk1 become sensitive to β-lactam antibiotics, implying that Stk1 could be an alternative target for combination therapy. However, the autophosphorylation mechanism of Stk1 remains elusive. Using a phosphoproteomic study, we identified six in vivo phosphorylated activatio ...[more]

PMID: 29731745

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Project description:Methicillin resistance in Staphylococcus aureus depends on the production of mecA, which encodes penicillin-binding protein 2A (PBP2A), an acquired peptidoglycan transpeptidase with reduced susceptibility to beta-lactam antibiotics. Here, we show that preventing the expression of wall teichoic acids (WTAs) genetically or with a TarO inhibitor sensitizes MRSA strains to beta-lactams although PBP2A is still expressed. Using S. aureus microarrays and array data analysis protocols (NIAID's Pathogen Functional Genomics Resource Center) we have characterized the transcriptomes of S. aureus COL. in order to further understand the sensitization of strain COL to methicillin by tunicamycin we determined the tunicamycin and methicillin transcriptomes alone and in combination. Methicillin treatment of COL at 500 Âµg/mL had almost no effect on cell growth rate and, remarkably, the only gene in the transcriptome that showed a more than two-fold change in expression was lytM, which was downregulated. The tunicamycin transcriptome of COL, acquired at 0.4 Âµg/mL, shows modest changes compared to the untreated control both in terms of the total numbers of affected genes and in the degree of up- or downregulation. Several of the genes upregulated upon tunicamycin treatment are part of the cell wall stress stimulon.COL was grown with methicillin to an OD600 ~0.4, and challenged with tunicamycin for 2 hrs whereas the control culture contained methicillin alone. transcriptome for COL growing in the presence of both agents showed extensive changes in gene expression. , the cell wall stress stimulon, which was not induced by methicillin when tunicamycin was absent, was clearly induced in its presence and the changes were far more dramatic than observed with tunicamycin alone. ). vraS and vraR, which encode a two component signaling system dedicated to the cell wall regulon, were upregulated 3.8 and 3.7 fold, respectively. Other upregulated cell wall stress stimulon genes include pbp2, fmtA, mvaD (mevalonate diphosphate decarboxylase), crtN (dehydrosqualene desaturase) mvak1 (mevalonate kinase), recU, SAV1424 (methionine sulfoxide reductase A), prsA (peptidyl-prolyl cis/trans isomerase), tcaA (Tca protein) and cwrA. A considerable number of genes were also downregulated upon challenge of COL with the combination of tunicamycin and methicillin. These included sspB, lrgA, dltA, capL, SAS0988, sspA, pflB, and spa. Several of these genes have been found to be downregulated in previous studies of cell wall-active antibiotic challenge of S. aureus. Growth conditions for microarray analysis- For transcriptional profiling, an overnight-grown COL culture was diluted (2% vol/vol) to 20 ml TSB medium in a 50-ml Erlenmeyer flask and grown at 30Â°C with shaking at 200 rpm. For the sensitization experiment, COL was grown with methicillin to an OD600 ~0.4, and challenged with tunicamycin for 2 hrs whereas the control culture contained methicillin alone. Total bacterial RNA was isolated as previously described from S. aureus COL (30Â°C, 200 rpm). The RNA samples were then converted to fluorescently-labeled cDNA and hybridized to S. aureus microarrays version 7 (NIAID's Pathogen Functional Genomics Resource Center). Hybridization signals were scanned using an Axon4000B scanner (Molecular Devices, Sunnyvale, CA ) with Acuity 4.0 software and scans were saved as TIFF image. Scans were analyzed using TIGR-Spotfinder (www.tigr.org/software/) software and the local background was subsequently subtracted. The data set was normalized by applying the LOWESS algorithm using TIGR-MIDAS (www.tigr.org/software/) software. The normalized log2 ratio of test/reference signal for each spot was recorded. Genes with less than three data points were considered unreliable, and their data points were discarded. The averaged log2 ratio for each remaining gene on the four replicate slides was ultimately calculated. Significant changes of gene expression were identified with SAM (significance analysis of microarrays; www.tat.stanford.edu/~tibs/SAM/index.html. Genes analyzed using these programs were further sorted and grouped based on their function using our in-house software Staphylococcus aureus Gene Sorter (SAGS). Several controls were employed to minimize the technical and biological variations and to ensure that the data obtained were of good quality. First, each ORF was present in triplicate on the array. Second, each RNA preparation was used to make probes for at least two separate arrays for which the incorporated dye was reversed. Contents of raw data files: Channel A = Cy3 dye Channel B = Cy5 dye File names ending with S1,S3 = Cy3 untreated, Cy5 treated File names ending with S2,S4 = Cy5 untreated, Cy3 treated

Project description:The transcription level of a rex-deficient S. aureus mutant in comparison to its parental strain S. aureus SH1000 was analyzed using DNA microarrays. S. aureus N315 microarrays were purchased from Scienion (Scienion AG, Berlin, Germany) and were produced by spotting 2,338 PCR products of the 2,593 ORFs comprising annotated genome of S. aureus N315 [reference identification: NC_002745] on a glass slide. Each ORF is present in duplicate on the microarray (further details can be found at http://www.scienion.com), cDNA was synthesized from total RNA with the LabelStar Array Kit from QIAGEN using the QIAGEN protocol with slight modifications: Random hexamer primer were used (Invitrogen, Karlsruhe, Germany) and Cy3- and Cy5-dCTP were purchased from Perkin-Elmer (Rodgau - Juegesheim, Germany). As recommended by Scienion, 10 Âµg RNA from either SH1000 or AK1 were used for cDNA synthesis. After hybridisation for 72 h, the microarrays were washed as recommended by the manufacturer. Data analysis. The hybridized microarrays were scanned with a GenePix 4000B microarray scanner (MDS Analytical Technologies GmbH, Ismaning, Germany). A geometric raster was laid over the resulting microarray picture to distinguish the signals from the background. After localization of single spots, intensities and global background were calculated automatically. The hybridization patterns and intensities were quantitatively analyzed using the Imagene 6 software (BioDiscovery, El Segundo, CA). The replicates were averaged, and the spots identified by Imagene 6 (BioDiscovery) as flawed were omitted. The data set was normalized by application of the LOWESS algorithm. In a next step, the intensity values of all arrays for each time point as well as for all time points combined were used for t tests. Genes with a change of <0.5- or â?¥2.0-fold were characterized as having significantly differing amounts of transcripts based on t tests with a P value cut-off of at least 0.05. Gene functions were assigned to the respective accession numbers and annotations as compiled on DOGAN, a web page for S. aureus N315 (http://www.bio.nite.go.jp/dogan/MicroTop?GENOME_ID=n315G1). The parental strain SH1000 and the Rex deficient mutant AK1 were applied on full-genome microarrays to get a detailed view on the differences in the transcriptional profiles which are caused â?? directly or indirectly â?? by the introduced mutation. More specifically, expression levels were compared at five time points, covering different growth phases. To highlight the general changes in the expression profile between SH1000 and the rex mutant, the microarray data of all five time points were also analyzed in a combined way using standard statistical methods. In further experiments, we focused on those genes, which seemed to flag the general difference between the investigated strains.

Dataset Information

Phosphoproteomic analysis of Staphylococcus aureus

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Publications

Autophosphorylation Mechanism of the Ser/Thr Kinase Stk1 From <i>Staphylococcus aureus</i>.

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