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Burnside K, Lembo A, Harrell MI, Gurney M, Xue L, BinhTran NT, Connelly JE, Jewell KA, Schmidt BZ, de Los Reyes M, Tao WA, Doran KS, Rajagopal L. Serine/threonine phosphatase Stp1 mediates post-transcriptional regulation of hemolysin, autolysis, and virulence of group B Streptococcus. J Biol Chem 2011; 286:44197-44210. [PMID: 22081606 DOI: 10.1074/jbc.m111.313486] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Elucidating how serine/threonine phosphatases regulate kinase function and bacterial virulence is critical for our ability to combat these infections. Group B streptococci (GBS) are β-hemolytic Gram-positive bacteria that cause invasive infections in humans. To adapt to environmental changes, GBS encodes signaling mechanisms comprising two component systems and eukaryotic-like enzymes. We have previously described the importance of the serine/threonine kinase Stk1 to GBS pathogenesis. However, how the presence or absence of the cognate serine/threonine phosphatase Stp1 affects Stk1 function and GBS virulence is not known. Here, we show that GBS deficient only in Stp1 expression are markedly reduced for their ability to cause systemic infections, exhibit decreased β-hemolysin/cytolysin activity, and show increased sensitivity to autolysis. Although transcription of genes important for β-hemolysin/cytolysin expression and export is similar to the wild type (WT), 294 genes (excluding stp1) showed altered expression in the stp1 mutant and included autolysin genes. Furthermore, phosphopeptide enrichment analysis identified that 35 serine/threonine phosphopeptides, corresponding to 27 proteins, were unique to the stp1 mutant. This included phosphorylation of ATP synthase, DNA and RNA helicases, and proteins important for cell division and protein synthesis. Collectively, our results indicate that Stp1 is important for appropriate regulation of Stk1 function, hemolysin activity, autolysis, and GBS virulence.
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Affiliation(s)
- Kellie Burnside
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Annalisa Lembo
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Maria Isabel Harrell
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Michael Gurney
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California 92182
| | - Liang Xue
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
| | - Nguyen-Thao BinhTran
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - James E Connelly
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Kelsea A Jewell
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Byron Z Schmidt
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Melissa de Los Reyes
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Weiguo Andy Tao
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
| | - Kelly S Doran
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California 92182
| | - Lakshmi Rajagopal
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101.
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Wang CW, Chen WC, Lin LJ, Lee CT, Tseng TH, Leu WM. OIP30, a RuvB-Like DNA Helicase 2, is a Potential Substrate for the Pollen-Predominant OsCPK25/26 in Rice. ACTA ACUST UNITED AC 2011; 52:1641-56. [DOI: 10.1093/pcp/pcr094] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Tyagi S, Ochem A, Tyagi M. DNA-dependent protein kinase interacts functionally with the RNA polymerase II complex recruited at the human immunodeficiency virus (HIV) long terminal repeat and plays an important role in HIV gene expression. J Gen Virol 2011; 92:1710-1720. [PMID: 21450944 DOI: 10.1099/vir.0.029587-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
DNA-dependent protein kinase (DNA-PK), a nuclear protein kinase that specifically requires association with DNA for its kinase activity, plays important roles in the regulation of different DNA transactions, including transcription, replication and DNA repair, as well as in the maintenance of telomeres. Due to its large size, DNA-PK is also known to facilitate the activities of other factors by providing the docking platform at their site of action. In this study, by running several chromatin immunoprecipitation assays, we demonstrate the parallel distribution of DNA-PK with RNA polymerase II (RNAP II) along the human immunodeficiency virus (HIV) provirus before and after activation with tumour necrosis factor alpha. The association between DNA-PK and RNAP II is also long-lasting, at least for up to 4 h (the duration analysed in this study). Knockdown of endogenous DNA-PK using specific small hairpin RNAs expressed from lentiviral vectors resulted in significant reduction in HIV gene expression and replication, demonstrating the importance of DNA-PK for HIV gene expression. Sequence analysis of the HIV-1 Tat protein revealed three potential target sites for phosphorylation by DNA-PK and, by using kinase assays, we confirmed that Tat is an effective substrate of DNA-PK. Through peptide mapping, we found that two of these three potential phosphorylation sites are recognized and phosphorylated by DNA-PK. Mutational studies on the DNA-PK target sites of Tat further demonstrated the functional significance of the Tat-DNA-PK interaction. Thus, overall our results clearly demonstrate the functional interaction between DNA-PK and RNAP II during HIV transcription.
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Affiliation(s)
- Shilpi Tyagi
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Wernher and Beit Building (South), Anzio Road, Observatory 7925, Cape Town, South Africa.,National Center for Biodefense and Infectious Diseases, George Mason University, Biomedical Research Laboratory, 10650 Pyramid Place, MS 1J5, Manassas, VA 20110, USA
| | - Alex Ochem
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Wernher and Beit Building (South), Anzio Road, Observatory 7925, Cape Town, South Africa
| | - Mudit Tyagi
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Adelbert Road, Cleveland, OH 44106, USA.,National Center for Biodefense and Infectious Diseases, George Mason University, Biomedical Research Laboratory, 10650 Pyramid Place, MS 1J5, Manassas, VA 20110, USA
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