Timothy L. Yahr, PhD

Portrait
Director of Graduate Studies
Professor of Microbiology and Immunology

Contact Information

Office: 200A Eckstein Medical Research Building
431 Newton Rd
Iowa City, IA 52242
319-335-9688

Lab: 200N Eckstein Medical Research Building
431 Newton Rd
Iowa City, IA 52242
319-335-8666

Education

BS, Biology, University of Wisconsin-Stevens Point
MS, Microbiology, Medical College of Wisconsin
PhD, Microbiology, Medical College of Wisconsin

Post Doctoral Fellow, Biochemistry, Dartmouth Medical School

Education/Training Program Affiliations

Biomedical Science Program, Department of Microbiology Graduate Program, Interdisciplinary Graduate Program in Translational Biomedicine, Medical Scientist Training Program

Center, Program and Institute Affiliations

Center for Biocatalysis and Bioprocessing, Center for Gene Therapy of Cystic Fibrosis and other Genetic Diseases

Research Summary

My laboratory studies regulation of the Pseudomonas aeruginosa type III secretion system (T3SS). T3SS's are unique to Gram-negative bacteria and function to deliver toxins into eukaryotic host cells. The secretion machinery consists of ~30 proteins which span both the inner and outer membranes of the bacterial cell. Following contact of the bacterium with a eukaryotic cell, the type III machinery functions like a molecular syringe to inject toxins into the host cell. Expression of the P. aeruginosa T3SS is highly regulated and induced by at least two environmental cues; contact of the bacteria with eukaryotic cells and growth in the presence of low Ca2+ concentrations. In the absence of these cues, low amounts of the type III secretion channels are assembled within the cell membranes. The channels, however, are inactive and expression of the T3SS is repressed. Expression of the T3SS genes is coupled to type III secretory activity by a cascade of interacting regulatory proteins (ExsA, ExsD, ExsC, and ExsE). ExsA is an activator of type III gene transcription, ExsD binds ExsA to inhibit transcription, ExsC inhibits ExsD activity, and ExsE inhibits ExsC activity. The entire process is coupled to secretion by virtue of the fact that ExsE is a secreted substrate of the T3SS. Changes in the intracellular concentration of ExsE are thought to govern formation of the ExsC-ExsE, ExsC-ExsD, and ExsD-ExsA complexes. Whereas formation of the ExsC-ExsE complex allows ExsD to bind ExsA and transcription of the T3SS is repressed, formation of the ExsC-ExsD complex sequesters ExsD from ExsA and transcription of the T3SS is induced. The major efforts in my lab involve testing the above model and determining how this regulatory cascade interfaces with a number of additional regulatory mechanisms also controlling T3SS gene expression.

Publications

Kroken, A., Chen, C., Evans, D., Yahr, T. L. & Fleiszig, S. (2018). P. aeruginosa internalization into epithelial cells is associated with intracellular triggering of the type three secretion system. ARVO, Honolulu, HI.

Williams McMackin, E. A., Marsden, A. E., Cribbs, J. T. & Yahr, T. L. (2017). Histone-like proteins MvaT and MvaU inhibit type III secretion in Pseudomonas aeruginosa. Midwest Microbial Pathogenesis Meeting, Notre Dame, IN.

Schulmeyer, K. H., Diaz, M. R., Golden, M., Wolfgang, M. C. & Yahr, T. L. (2017). Functional analyses of the RsmY and RsmZ small non-coding regulatory RNAs in Pseudomonas aeruginosa. Midwest Microbial Pathogenesis Meeting, Notre Dame, IN.

Schulmeyer, K. H., Yahr, T. L. (2017). Post-transcriptional regulation of type III secretion in plant and animal pathogens. Curr Opin Microbiol, 36, 30-36. PMID: 28189908.

Chakravarty, S., Melton, C. N., Bailin, A., Yahr, T. L. & Anderson, G. G. (2017). Pseudomonas aeruginosa Magnesium Transporter MgtE Inhibits Type III Secretion System Gene Expression by Stimulating rsmYZ Transcription. J Bacteriol, 199(23), e00268-17. PMID: 28847924.

Chakravarty, S., Melton, C. N., Yahr, T. L. & Anderson, G. G. (2017). Molecular Mechanism of MgtE mediated Type Three Secretion System Inhibition in Pseudomonas aeruginosa. General Meeting of the American Society for Microbiology, New Orleans, LA.

Anantharajah, A., Faure, E., Buyck, J. M., Sundin, C., Lindmark, T., Mecsas, J., Yahr, T. L., Tulkens, P. M., Mingeot-Leclercq, M. P., Guery, B. & Van Bambeke, F. (2016). Inhibition of the Injectisome and Flagellar Type III Secretion Systems by INP1855 Impairs Pseudomonas aeruginosa Pathogenicity and Inflammasome Activation. J Infect Dis, 214(7), 1105-16. PMID: 27412581.

Schulmeyer, K. H., Diaz, M. R., Bair, T. B., Sanders, W., Gode, C. J., Laederach, A., Wolfgang, M. C. & Yahr, T. L. (2016). Primary and Secondary Sequence Structure Requirements for Recognition and Discrimination of Target RNAs by Pseudomonas aeruginosa RsmA and RsmF. J Bacteriol, 198(18), 2458-69. PMID: 27381913.

Chakravarty, S., Bailin, A. M., Yahr, T. L. & Anderson, G. G. (2016). The Pseudomonas aeruginosa magnesium transporter mgtE reduces translation of the Type III Secretion System transcription factor exsA. Midwest Microbial Pathogenesis Meeting, Champaign, IL.

Schulmeyer, K., Diaz, M., Bair, T., Hoinka, J., Przytycka, T., Sanders, W., Gode, C., Laederach, A., Wolfgang, M. & Yahr, T. L. (2016). Primary and secondary sequence structure requirements for recognition and discrimination of target RNAs by Pseudomonas aeruginosa RsmA and RsmF. Intelligent Systems for Molecular Biology, Orlando, FL.

Fischer, A., Shanrock, C., Yahr, T. L. & Welsh, M. (2016). Dithiothreitol releases bacteria-laden mucus strains from CF pig tracheas. North American Cystic Fibrosis Meeting, Orlando, FL.

Bailin, A., Yahr, T. L. (2016). The diguanylate cyclase YfiN alters exsA transcription to inhibit expression of the Type III Secretion System in Pseudomonas aeruginosa. Midwest Microbial Pathogenesis Meeting, Champaign, IL.

Marsden, A. E., Intile, P. J., Schulmeyer, K. H., Simmons-Patterson, E. R., Urbanowski, M. L., Wolfgang, M. C. & Yahr, T. L. (2016). Vfr Directly Activates exsA Transcription To Regulate Expression of the Pseudomonas aeruginosa Type III Secretion System. J Bacteriol, 198(9), 1442-50. PMID: 26929300.

Bailin, A., Diaz, M. R., Urbanowski, M. L., Intile, P. J., Wolfgang, M. C. & Yahr, T. L. (2015). RsmA-dependent post-transcriptional activation of ExsA synthesis. ASM Conference on Pseudomonas, Washington, DC.

Jorth, P., Staudinger, B. J., Wu, X., Hisert, K. B., Hayden, H., Garudathri, J., Harding, C. L., Radey, M. C., Rezayat, A., Bautista, G., Berrington, W. R., Goddard, A. F., Zheng, C., Angermeyer, A., Brittnacher, M. J., Kitzman, J., Shendure, J., Fligner, C. L., Mittler, J., Aitken, M. L., Manoil, C., Bruce, J. E., Yahr, T. L. & Singh, P. K. (2015). Regional Isolation Drives Bacterial Diversification within Cystic Fibrosis Lungs. Cell Host Microbe, 18(3), 307-19. PMID: 26299432.

Marsden, A. E., King, J. M., Spies, M. A., Kim, O. K. & Yahr, T. L. (2015). Inhibition of Pseudomonas aeruginosa ExsA DNA-Binding Activity by N-Hydroxybenzimidazoles. Antimicrob Agents Chemother, 60(2), 766-76. PMID: 26574012.

Diaz, M. R., Schulmeyer, K. H., Hoinka, J., Przytycka, T., Wolfgang, M. C. & Yahr, T. L. (2015). Determining the mechanistic basis for differential binding by RsmA and RsmF. ASM Conference on Pseudomonas, Washington, DC.

Intile, P. J., Balzer, G. J., Wolfgang, M. C. & Yahr, T. L. (2015). The RNA helicase DeaD stimulates ExsA translation to promote expression of the Pseudomonas aeruginosa type III secretion system. J Bacteriol, 197(16), 2664-74. PMID: 26055113.

Ince, D., Sutterwala, F. S. & Yahr, T. L. (2015). Secretion of Flagellar Proteins by the Pseudomonas aeruginosa Type III Secretion-Injectisome System. J Bacteriol, 197(12), 2003-11. PMID: 25845843.

Intile, P. I., Balzer, G. B., Wolfgang, M. C. & Yahr, T. L. (2014). The RNA-Helicase DeaD activates ExsA translation to promote expression of the Pseudomonas aeruginosa type III secretion system. Midwest Microbial Pathogenesis Meeting, Chicago, IL.

Marsden, A. E., Yahr, T. L. (2014). Amino-Terminal Residues of ExsA Are Required for Self-Association and Interaction with the ExsD Anti-Activator. General Meeting of the American Society for Microbiology, Boston, MA.

Intile, P. J., Diaz, M. R., Urbanowski, M. L., Wolfgang, M. C. & Yahr, T. L. (2014). The AlgZR Two-Component System Recalibrates the RsmAYZ Posttranscriptional Regulatory System To Inhibit Expression of the Pseudomonas aeruginosa Type III Secretion System. J Bacteriol, 196(2), 357-66. PMID: 24187093.

Marsden, A. E., Schubot, F. D. & Yahr, T. L. (2014). Self-association of ExsA is required for occupation of adjacent binding sites on Pseudomonas aeruginosa type III secretion system promoters. J Bacteriol, 196(20), 3546-55. PMID: 25070741.

Marsden, A. E., Yahr, T. L. (2013). Residues in the amino-terminal domain of ExsA are required for self-association and interaction with the ExsD anti-activator. Molecular Genetics of Bacteria and Phages Meeting, Madison, WI.

Intile, P. I., Diaz, M. R., Urbanowski, M. L., Wolfgang, M. C. & Yahr, T. L. (2013). The AlgZR two-component system recalibrates the RsmAYZ post-transcriptional regulatory system to inhibit expression of the Pseudomonas aeruginosa type III secretion system. Molecular Genetics of Bacteria and Phages Meeting, Madison, WI.

King, J. M., Bartra, S. S., Plano, G. V. & Yahr, T. L. (2013). Reexamining the DNA binding properties of LcrF from Yersinia pestis. General Meeting of the American Society for Microbiology, Denver, CO.

Heimer, S. R., Evans, D. J., Stern, M. E., Barbieri, J. T., Yahr, T. & Fleiszig, S. M. (2013). Pseudomonas aeruginosa Utilizes the Type III Secreted Toxin ExoS to Avoid Acidified Compartments within Epithelial Cells. PLoS One, 8(9), e73111. PMID: 24058462.

Berhards, R. C., Marsden, A. E., Esher, S. K., Yahr, T. L. & Schubot, F. D. (2013). Self-trimerization of ExsD limits inhibition of the Pseudomonas aeruginosa transcriptional activator ExsA in vitro. FEBS J, 280(4), 1084-94. PMID: 23279839.

King, J. M., Schesser Bartra, S., Plano, G. & Yahr, T. L. (2013). ExsA and LcrF recognize similar consensus binding sites, but differences in their oligomeric state influence interactions with promoter DNA. J Bacteriol, 195(24), 5639-50. PMID: 24142246.

Marden, J. N., Diaz, M. R., Walton, W. G., Gode, C. J., Betts, L., Urbanowski, M. L., Redinbo, M. R., Yahr, T. L. & Wolfgang, M. C. (2013). An unusual CsrA family member operates in series with RsmA to amplify posttranscriptional responses in Pseudomonas aeruginosa. Proc Natl Acad Sci U S A, 110(37), 15055-60. PMID: 23980177.

Olson, M. E., King, J. M., Yahr, T. L. & Horswill, A. R. (2013). Sialic Acid Catabolism in Staphylococcus aureus. J Bacteriol, 195(8), 1779-88. PMID: 23396916.

Intile, P. J., Urbanowski, M. L., Wolfgang, M. C. & Yahr, T. L. (2012). The AlgZR two-component system recalibrates the RsmAYZ post-transcriptional regulatory system to inhibit ExsA expression in Pseudomonas aeruginosa ?mucA isolates. Midwest Microbial Pathogenesis Meeting, Medical College of Wisconsin, Milwaukee, WI.

Diaz, M. R., Urbanowski, M. L., Wolfgang, M. C. & Yahr, T. L. (2012). RsmA exerts a positive regulatory effect on ExsA expression at the post-transcriptional level. Midwest Microbial Pathogenesis Meeting, Medical College of Wisconsin, Milwaukee, WI.

King, J. M., Bartra, S. S., Plano, G. V. & Yahr, T. L. (2012). The transcriptional activators of T3SS gene expression in Pseudomonas aeruginosa, Yersinia pestis, Aeromonas hydrophila, Photorhabdus luminescens, and Vibrio parahaemolyticus recognize a common sequence. Midwest Microbial Pathogenesis Meeting, Medical College of Wisconsin, Milwaukee, WI.

King, J. M., Brutinel, E. D., Marsden, A. E., Schubot, F. D. & Yahr, T. L. (2012). Orientation of Pseudomonas aeruginosa ExsA monomers bound to promoter DNA and base-specific contacts with the P(exoT) promoter. J Bacteriol, 194(10), 2573-85. PMID: 22408167.

Marsden, A. E., Schubot, F. & Yahr, T. L. (2012). Identification of residues in the Pseudomonas aeruginosa transcriptional activator ExsA involved in self-association and interaction with the inhibitor ExsD. Midwest Microbial Pathogenesis Meeting, Medical College of Wisconsin, Milwaukee, WI.

Brutinel, E. D., King, J. M., Marsden, A. E. & Yahr, T. L. (2012). The distal ExsA-binding site in Pseudomonas aeruginosa type III secretion system promoters is the primary determinant for promoter-specific properties. J Bacteriol, 194(10), 2564-72. PMID: 22408165.

Zheng, Z., Ma, D., Yahr, T. L. & Chen, L. (2012). The transiently ordered regions in intrinsically disordered ExsE are correlated with structural elements involved in chaperone binding. Biochem Biophys Res Commun, 417(1), 129-34. PMID: 22138394.

Ahlgren, H., Bauerle, E., Yahr, T. L., Singh, P. & Nguyen, D. (2011). The stringent response controls virulence in Pseudomonas aeruginosa. The 25th Annual North American Cystic Fibrosis Conference, Anaheim, CA.

Brutinel, E. D., King, J. & Yahr, T. L. (2011). The affinity of ExsA for promoter DNA, promoter strength, and the degree of promoter bending are determined by the distal ExsA binding site of T3SS promoters in Pseudomonas aeruginosa. General Meeting of the American Society for Microbiology, New Orleans, LA.

Diaz, M. R., Urbanowski, M. L., Wolfgang, M. C. & Yahr, T. L. (2011). RsmA exerts a positive regulatory effect on ExsA expression at a post-transcriptional level. General Meeting of the American Society for Microbiology, New Orleans, LA.

Pezzulo, A. A., Gutiérrez, J., Duschner, K. S., McConnell, K. S., Taft, P. J., Ernst, S. E., Yahr, T. L., Rahmouni, K., Klesney-Tait, J., Stoltz, D. A. & Zabner, J. (2011). Glucose depletion in the airway surface liquid is essential for sterility of the airways. PLoS One, 6(1), e16166. PMID: 21311590.

Diaz, M. R., King, J. M. & Yahr, T. L. (2011). Intrinsic and Extrinsic Regulation of Type III Secretion Gene Expression in Pseudomonas aeruginosa. Front Microbiol, 2, 89. PMID: 21833328.

Brutinel, E. D., King, J. & Yahr, T. L. (2010). The affinity of ExsA for promoter DNA, promoter strength, and the degree of promoter bending are determined by the distal ExsA binding site of T3SS promoters in Pseudomonas aeruginosa. Midwest Microbial Pathogenesis Meeting, Washington University, St Louis, MO.

Urbanowski, M. L., Balzer, G., Wolfgang, M. C. & Yahr, T. L. (2010). The RsmA and MucA/AlgU Regulatory Systems Independently Control ExsA Expression at the Post-transcriptional Level. General Meeting of the American Society for Microbiology, San Diego, CA.

Urbanowski, M. L., Balzer, G., Wolfgang, M. C. & Yahr, T. L. (2010). The RsmA and MucA/AlgU Regulatory Systems Independently Control ExsA Expression at the Post-transcriptional Level. Midwest Microbial Pathogenesis Meeting, Washington University, St Louis, MO.

Anderson, G. G., Yahr, T. L., Lovewell, R. R. & O'Toole, G. A. (2010). The Pseudomonas aeruginosa magnesium transporter MgtE inhibits transcription of the type III secretion system. Infect Immun, 78(3), 1239-49. PMID: 20028803.

Vakulskas, C. A., Brutinel, E. D. & Yahr, T. L. (2010). ExsA recruits RNA polymerase to an extended -10 promoter by contacting region 4.2 of sigma-70. J Bacteriol, 192(14), 3597-607. PMID: 20453093.

Brutinel, E. D., Vakulskas, C. A. & Yahr, T. L. (2010). ExsD inhibits expression of the Pseudomonas aeruginosa type III secretion system by disrupting ExsA self-association and DNA binding activity. J Bacteriol, 192(6), 1479-86. PMID: 20008065.

Jones, A. K., Fulcher, N. B., Balzer, G. J., Urbanowski, M. L., Pritchett, C. L., Schurr, M. J., Yahr, T. L. & Wolfgang, M. C. (2010). Activation of the Pseudomonas aeruginosa AlgU regulon through mucA mutation inhibits cyclic AMP/Vfr signaling. J Bacteriol, 192(21), 5709-17. PMID: 20817772.

Fuchs, E. L., Brutinel, E. D., Jones, A. K., Fulcher, N. B., Urbanowski, M. L., Yahr, T. L. & Wolfgang, M. C. (2010). The Pseudomonas aeruginosa Vfr regulator controls global virulence factor expression through cyclic AMP-dependent and -independent mechanisms. J Bacteriol, 192(14), 3553-64. PMID: 20494996.

Fuchs, E. L., Brutinel, E. D., Klem, E. R., Fehr, A. R., Yahr, T. L. & Wolfgang, M. C. (2010). In vitro and in vivo characterization of the Pseudomonas aeruginosa cyclic AMP (cAMP) phosphodiesterase CpdA, required for cAMP homeostasis and virulence factor regulation. J Bacteriol, 192(11), 2779-90. PMID: 20348254.

Ince, D., Wang, D., Hopp, C. & Yahr, T. L. (2009). Secretion of flagellar proteins through the Pseudomonas aeruginosa injectisome system. Midwest Microbial Pathogenesis Meeting, West Lafayette, IN.

Jones, A. K., Balzer, G., Yahr, T. L., Fulcher, N. B. & Wolfgang, M. C. (2009). The MucA pathway contributes to reciprocal regulation of acute and chronic virulence factors in Pseudomonas aeruginosa. Mid-Atlantic Microbial Pathogenesis Meeting, Wintergreen Conference Center, VA.

Anderson, G. G., Yahr, T. L. & O'Toole, G. A. (2009). Inhibition of Pseudomonas aeruginosa Toxicity Toward Airway Epithelial Cells. North American Cystic Fibrosis Conference, Minneapolis, MN.

Brutinel, E. D., Vakulskas, C. A. & Yahr, T. L. (2009). Functional domains of ExsA, the transcriptional activator of the Pseudomonas aeruginosa type III secretion system. J Bacteriol, 191(12), 3811-21. PMID: 19376850.

Vakulskas, C. A., Brady, K. M. & Yahr, T. L. (2009). Mechanism of transcriptional activation by Pseudomonas aeruginosa ExsA. J Bacteriol, 191(21), 6654-64. PMID: 19717612.

Urbanowski, M. L., Yahr, T. L. (2008). Limiting too much of a good thing: a negative feedback mechanism prevents unregulated translocation of type III effector proteins. (Vols. 190). (8), pp. 2643-4. J Bacteriol. PMID: 18083800.

Brutinel, E. D., Yahr, T. L. (2008). Control of gene expression by type III secretory activity. Curr Opin Microbiol, 11(2), 128-33. PMID: 18396449.

Brutinel, E. D., Vakulskas, C. A., Brady, K. M. & Yahr, T. L. (2008). Characterization of ExsA and of ExsA-dependent promoters required for expression of the Pseudomonas aeruginosa type III secretion system. Mol Microbiol, 68(3), 657-71. PMID: 18373522.

Vakulskas, C., Brady, K. M. & Yahr, T. L. (2008). Mechanism of Transcriptional Activation by Pseudomonas aeruginosa ExsA. Gordon Research Conference on Microbial Toxins and Pathogenesis, Andover, NH.

Brady, K., Yahr, T. L. (2008). Identifying intrinsic structural properties in type III secretion promoters and the role they play in ExsA-dependent transcriptional activation in Pseudomonas aeruginosa. General Meeting of the American Society for Microbiology, Boston, MA.

Vakulskas, C., Yahr, T. L. (2008). Mechanism of Transcriptional Activation of T3SS Promoters in Pseudomonas aeruginosa by ExsA. General Meeting of the American Society for Microbiology, Boston, MA.

Brutinel, E., Yahr, T. L. (2008). Characterization of ExsA functional domains, the Transcriptional Activator of the Pseudomonas aeruginosa Type III Secretion System. General Meeting of the American Society for Microbiology, Boston, MA.

Anderson, G., Yahr, T. L. & O'Toole, G. A. (2008). The Pseudomonas aeruginosa Magnesium Transporter MgtE Affects Type III Secretion. North American Cystic Fibrosis Conference, Orlando, FL.

Brutinel, E., Vakulskas, C. & Yahr, T. L. (2007). DNA Binding Characteristics of ExsA; The Transcriptional Regulator of Type III Secretion in Pseudomonas aeruginosa. Phage Meeting, Madison, WI.

Jones, A. K., Balzer, G., Yahr, T. L., Fulcher, N. & Wolfgang, M. C. (2007). Mechanism for Reciprocal Regulation of Pseudomonas aeruginosa Virulence Factors that Contribute to Acute and Chronic Respiratory Infection. Mid-Atlantic Microbial Pathogenesis Meeting, Wintergreen, VA.

Brutinel, E., Vakulskas, C. & Yahr, T. L. (2007). Characterization of the ExsA Box, a Promoter Element Required for Transcription of Genes Encoding the Pseudomonas aeruginosa Type III Secretion System. General Meeting of the American Society for Microbiology, Toronto, Canada.

Song, Y., Fairman, J., Sawa, T., Liggitt, D., Yahr, T. L. & Wiener-Kronish, J. (2007). Cationic lipid DNA complexes (CLDC)/PcrV as a vaccine against Pseudomonas aeruginosa pneumonia. Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), San Francisco, CA.

Ashare, A., Monick, M. M., Nymon, A. B., Morrison, J. M., Noble, M., Powers, L. S., Yarovinsky, T. O., Yahr, T. L. & Hunninghake, G. W. (2007). Pseudomonas aeruginosa delays Kupffer cell death via stabilization of the X-chromosome-linked inhibitor of apoptosis protein. J Immunol, 179(1), 505-13. PMID: 17579071.

Urbanowski, M. L., Brutinel, E. D. & Yahr, T. L. (2007). Translocation of ExsE into Chinese hamster ovary cells is required for transcriptional induction of the Pseudomonas aeruginosa type III secretion system. Infect Immun, 75(9), 4432-9. PMID: 17635873.

Wu, Y., Xu, Z., Henderson, F. C., Ryan, A. J., Yahr, T. L. & Mallampalli, R. K. (2007). Chronic Pseudomonas aeruginosa infection reduces surfactant levels by inhibiting its biosynthesis. Cell Microbiol, 9(4), 1062-72. PMID: 17166234.

Zheng, Z., Chen, G., Joshi, S., Brutinel, E. D., Yahr, T. L. & Chen, L. (2007). Biochemical characterization of a regulatory cascade controlling transcription of the Pseudomonas aeruginosa type III secretion system. J Biol Chem, 282(9), 6136-42. PMID: 17197437.

Yahr, T. L., Parsek, M. R. (2006). Pseudomonas aeruginosa. In M. Dworkin , S. Falkow , E. Rosenberg , K. Schleifer , E. Stackebrandt (Eds.) The Prokaryotes. pp. 704-13. Springer. DOI: 10.1007/0-387-30746-x_22.

Urbanowski, M. L., Yahr, T. L. (2006). ExsE is translocated into host cells by the Pseudomonas aeruginosa type III secretion system. General Meeting of the American Society for Microbiology, Orlando, FL.

Dasgupta, N., Ashare, A., Hunninghake, G. & Yahr, T. L. (2006). Induction of the Pseudomonas aeruginosa type III secretion system by low Ca2+ and host cell contact proceeds through two distinct signaling pathways. General Meeting of the American Society for Microbiology, Orlando, FL.

Dasgupta, N., Ashare, A., Hunninghake, G. W. & Yahr, T. L. (2006). Transcriptional induction of the Pseudomonas aeruginosa type III secretion system by low Ca2+ and host cell contact proceeds through two distinct signaling pathways. Infect Immun, 74(6), 3334-41. PMID: 16714561.

Lykken, G. L., Chen, G., Brutinel, E. D., Chen, L. & Yahr, T. L. (2006). Characterization of ExsC and ExsD self-association and heterocomplex formation. J Bacteriol, 188(19), 6832-40. PMID: 16980486.

Yahr, T. L., Wolfgang, M. C. (2006). Transcriptional regulation of the Pseudomonas aeruginosa type III secretion system. Mol Microbiol, 62(3), 631-40. PMID: 16995895.

Yahr, T. L. (2006). A critical new pathway for toxin secretion?. (Vols. 355). (11), pp. 1171-2. N Engl J Med. PMID: 16971725.

Urbanowski, M. L., Yahr, T. L. (2005). The ExsE regulatory protein is translocated into host cells by the Pseudomonas aeruginosa type III secretion system. Midwest Microbial Pathogenesis Meeting, Minneapolis, MN.

Urbanowski, M. L., Lykken, G. L. & Yahr, T. L. (2005). A secreted regulatory protein couples transcription to the secretory activity of the Pseudomonas aeruginosa type III secretion system. Proc Natl Acad Sci U S A, 102(28), 9930-5. PMID: 15985546.

Lykken, G. L., Yahr, T. L. (2004). Role of an anti-activator and an anti-anti-activator in controlling expression of Pseudomonas aeruginosa type III secretion. General Meeting of the American Society for Microbiology, New Orleans, LA.

Dasgupta, N., Lykken, G. L., Wolfgang, M. C. & Yahr, T. L. (2004). A novel anti-anti-activator mechanism regulates expression of the Pseudomonas aeruginosa type III secretion system. Mol Microbiol, 53(1), 297-308. PMID: 15225323.

Yahr, T. L., Greenberg, E. P. (2004). The genetic basis for the commitment to chronic versus acute infection in Pseudomonas aeruginosa. (Vols. 16). (4), pp. 497-8. Mol Cell. PMID: 15546607.

Dasgupta, N., Wolfgang, M. & Yahr, T. L. (2003). ExsC is required for expression of the Pseudomonas aeruginosa type III secretion system. Pseudomonas 2003 Meeting, Quebec City, Canada.

McCaw, M. L., Lykken, G. L., Singh, P. K. & Yahr, T. L. (2002). ExsD is a negative regulator of the Pseudomonas aeruginosa type III secretion regulon. Mol Microbiol, 46(4), 1123-33. PMID: 12421316.

Yahr, T. L. (2002). ExsD is a negative regulator of type III secretion in Pseudomonas aeruginosa. General Meeting of the American Society for Microbiology, Salt Lake City, UT.

Yahr, T. L., Wickner, W. T. (2001). Investigations of the Escherichia coli twin-arginine protein translocase. General Meeting of the American Society for Microbiology, Orlando, FL.

Yahr, T. L., Wickner, W. T. (2001). Functional reconstitution of bacterial Tat translocation in vitro. EMBO J, 20(10), 2472-9. PMID: 11350936.

Yahr, T. L., Wickner, W. T. (2000). Evaluating the oligomeric state of SecYEG in preprotein translocase. EMBO J, 19(16), 4393-401. PMID: 10944122.

Frank, D. W., Yahr, T. L., Sawa, T., Barbancon-Finck, V. & Wiener-Kronish, J. P. (1999). Type III intoxication and Pseudomonas pathogenesis. Pseudomonas '99: Biotechnology and Pathogenesis, American Society for Microbiology, Maui, Hawaii.

Holder, I. A., Neely, A. N., Yahr, T. L. & Frank, D. W. (1999). Genetic analysis of the type III effectors of P. aeruginosa in the burned mouse model. General Meeting of the American Society for Microbiology, Chicago, IL.

Sawa, T., Yahr, T. L., Ohara, M., Kurahashi, K., Gropper, M. A., Wiener-Kronish, J. P. & Frank, D. W. (1999). Active and passive immunization with the Pseudomonas V antigen protects against type III intoxication and lung injury. Nat Med, 5(4), 392-8. PMID: 10202927.

Olson, J. C., Fraylick, J. E., McGuffie, E. M., Dolan, K. M., Yahr, T. L., Frank, D. W. & Vincent, T. S. (1999). Interruption of multiple cellular processes in HT-29 epithelial cells by Pseudomonas aeruginosa exoenzyme S. Infect Immun, 67(6), 2847-54. PMID: 10338490.

Vallis, A. J., Yahr, T. L., Barbieri, J. T. & Frank, D. W. (1999). Regulation of ExoS production and secretion by Pseudomonas aeruginosa in response to tissue culture conditions. Infect Immun, 67(2), 914-20. PMID: 9916108.

Vallis, A. J., Finck-Barbançon, V., Yahr, T. L. & Frank, D. W. (1999). Biological effects of Pseudomonas aeruginosa type III-secreted proteins on CHO cells. Infect Immun, 67(4), 2040-4. PMID: 10085057.

Sawa, T., Ohara, M., Kurahashi, K., Yahr, T. L., Gropper, M. A., Frank, D. W. & Wiener-Kronish, J. P. (1998). Pathogenesis of acute lung injury caused by Pseudomonas aeruginosa major contribution of type III secretory system. American Federation of Biomedical Research, Biomedicine.

Yahr, T. L., Vallis, A. J., Hancock, M. K. & Frank, D. W. (1998). ExoY, a novel type III secreted adenylate cyclase from Pseudomonas aeruginosa. General Meeting of the American Society for Microbiology, Atlanta, GA.

Ohara, M., Sawa, T., Kurahashi, K., Yahr, T. L., Frank, D. W., Wiener-Kronish, J. P. & Gropper, M. A. (1998). Pseudomonas aeruginosa inhibits Fc receptor-mediated phagocytosis. American Federation of Biomedical Research, Biomedicine.

Vallis, A. J., Yahr, T. L., Barbieri, J. T. & Frank, D. W. (1998). Contact-mediated regulation of ExoS production by Pseudomonas aeruginosa. General Meeting of the American Society for Microbiology, Atlanta, GA.

Finck-Barbançon, V., Yahr, T. L. & Frank, D. W. (1998). Identification and characterization of SpcU, a chaperone required for efficient secretion of the ExoU cytotoxin. J Bacteriol, 180(23), 6224-31. PMID: 9829931.

Yahr, T. L., Vallis, A. J., Hancock, M. K., Barbieri, J. T. & Frank, D. W. (1998). ExoY, an adenylate cyclase secreted by the Pseudomonas aeruginosa type III system. Proc Natl Acad Sci U S A, 95(23), 13899-904. PMID: 9811898.

Finck-Barbançon, V., Yahr, T. L. & Frank, D. W. (1998). Characterization of the exoU locus from Pseudomonas aeruginosa. General Meeting of the American Society for Microbiology, Atlanta, GA.

Yahr, T. L., Friese, M. B., Mende-Mueller, L. M. & Frank, D. W. (1997). Pseudomonas aeruginosa encodes homologs to the Yersinia lcrGVHyopBD locus. General Meeting of the American Society for Microbiology, Miami Beach, FL.

Yahr, T. L., Vallis, A. J., Friese, M. B., Mende-Mueller, L. M. & Frank, D. W. (1997). Identification and characterization of type III secreted products of the Pseudomonas aeruginosa exoenzyme S region. Midwest Microbial Pathogenesis Meeting, Ann Arbor, MI.

Vallis, A. J., Yahr, T. L. & Frank, D. W. (1997). Development of in vitro methodologies to study type III-mediated translocation of Pseudomonas aeruginosa ExoS. Midwest Microbial Pathogenesis Meeting, Ann Arbor, MI.

Liu, S., Yahr, T. L., Frank, D. W. & Barbieri, J. T. (1997). Biochemical relationships between the 53-kilodalton (Exo53) and 49-kilodalton (ExoS) forms of exoenzyme S of Pseudomonas aeruginosa. J Bacteriol, 179(5), 1609-13. PMID: 9045820.

Yahr, T. L., Mende-Mueller, L. M., Friese, M. B. & Frank, D. W. (1997). Identification of type III secreted products of the Pseudomonas aeruginosa exoenzyme S regulon. J Bacteriol, 179(22), 7165-8. PMID: 9371466.

Yahr, T. L., Goranson, J. & Frank, D. W. (1996). Exoenzyme S of Pseudomonas aeruginosa is secreted by a type III pathway. Gordon Research Conference on Microbial Toxins and Pathogenesis, Colby-Sawyer College, NH.

Yahr, T. L., Goranson, J. & Frank, D. W. (1996). Exoenzyme S of Pseudomonas aeruginosa is secreted by a type III pathway. General Meeting of the American Society for Microbiology, New Orleans, LA.

Yahr, T. L., Goranson, J. & Frank, D. W. (1996). Exoenzyme S of Pseudomonas aeruginosa is secreted by a type III pathway. Mol Microbiol, 22(5), 991-1003. PMID: 8971719.

Liu, S., Knight, D. A., Yahr, T. L. & Barbieri, J. T. (1996). Biochemical properties of the 53-kDa form of Pseudomonas aeruginosa exoenzyme S. General Meeting of the American Society for Microbiology, New Orleans, LA.

Yahr, T. L., Barbieri, J. T. & Frank, D. W. (1996). Genetic relationship between the 53- and 49-kilodalton forms of exoenzyme S from Pseudomonas aeruginosa. J Bacteriol, 178(5), 1412-9. PMID: 8631719.

Yahr, T. L., Barbieri, J. T. & Frank, D. W. (1995). The genetic relationship between the 49- and 53-kDa forms of exoenzyme S. General Meeting of the American Society for Microbiology, Washington, DC.

Yahr, T. L., Hovey, A. K., Kulich, S. M. & Frank, D. W. (1995). Transcriptional analysis of the Pseudomonas aeruginosa exoenzyme S structural gene. J Bacteriol, 177(5), 1169-78. PMID: 7868588.

Yahr, T. L., Frank, D. W. (1994). Transcriptional analysis of the exoenzyme S structural gene. Gordon Research Conference on Microbial Toxins and Pathogenesis, Colby-Sawyer College, NH.

Kulich, S. M., Yahr, T. L., Mende-Mueller, L. M., Barbieri, J. T. & Frank, D. W. (1994). Cloning the structural gene for the 49-kDa form of exoenzyme S (exoS) from Pseudomonas aeruginosa strain 388. J Biol Chem, 269(14), 10431-7. PMID: 8144626.

Yahr, T. L., Frank, D. W. (1994). Transcriptional organization of the trans-regulatory locus which controls exoenzyme S synthesis in Pseudomonas aeruginosa. J Bacteriol, 176(13), 3832-8. PMID: 8021164.

Yahr, T. L., Frank, D. W. (1992). Transcriptional organization of the exoenzyme S trans-regulatory locus in Pseudomonas aeruginosa. General Meeting of the American Society for Microbiology, Atlanta, GA.

Yahr, T. L., Frank, D. W. (1992). Transcriptional control of the trans-regulatory locus required for exoenzyme S synthesis in Pseudomonas aeruginosa. Gordon Research Conference on Microbial Toxins and Pathogenesis, Colby-Sawyer College, NH.

Hovey, A. K., Yahr, T. L. & Frank, D. W. (1992). Functional analysis of ExsA of Pseudomonas aeruginosa. General Meeting of the American Society for Microbiology, Atlanta, GA.