Division of Microbiology
School of Medicine
Loma Linda University
Loma Linda, CA 92350
Phone:(909) 558-1000 Ext. 83394
Bacteria mount internal alarms to escape or adapt to environmental change. These alarms change bacterial swimming direction (chemotaxis), surface (twitching) motility, gene expression, biofilm formation and the course of infection. Exact responses are species-specific but they are all modulated by chemosensory systems that consist of sensory receptors (chemoreceptors) and effector proteins. The chemosensory system we study contains a chemoreceptor called Aer-2 that is found in a number of pathogens including Pseudomonas aeruginosa and Vibrio cholerae. Aer-2 receptors contain PAS sensing domains, a common domain in nature that is used to bind cofactors and monitor various cellular conditions. The PAS domains of Aer-2 (one in PaAer-2 and two in VcAer-2) bind heme and respond to several diatomic oxy-gases. In the case of PaAer-2, upstream and downstream di-HAMP domains control the signaling state of the receptor in response to PAS signaling. In the case of VcAer-2, a duplicated N-terminal PAS-heme domain may serve a similar role to the N-terminal di-HAMP domain of PaAer-2. My lab is currently working to understand the steps from PAS-ligand binding, to PAS/HAMP and HAMP/HAMP signaling, the output response of the receptors and the resulting changes in bacterial behavior. In the example of Aer-2 receptors, we propose that this series of events are important for bacterial pathogenesis.
- Garcia D, Orillard E, Johnson MS and Watts KJ. 2017. Gas sensing and signaling in the PAS-heme domain of the Pseudomonas aeruginosa Aer2 receptor. J. Bacteriol. 199(18):3-17.
- Garcia D, Watts KJ, Johnson MS and Taylor BL. 2016. Delineating PAS-HAMP interaction surfaces and signalling-associated changes in the aerotaxis receptor Aer. Mol Microbiol 100:156-72.
- Airola MV, Huh D, Sukomon N, Widom J, Sircar R, Borbat PP, Freed JH, Watts KJ, and Crane BR. 2013. Architecture of the soluble receptor Aer2 indicates an in-line mechanism for PAS and HAMP domain signaling. Journal of Molecular Biology. 425(5):886-901.
- Airola MV, Sukomon N, Samanta D, Borbat PP, Freed JH, Watts KJ, and Crane BR. 2013. HAMP domain conformers that propagate opposite signals in bacterial chemoreceptors. PLOS Biology. 11(2):e1001479.
- Watts KJ, Johnson MS, and Taylor BL. 2011. Different Conformations of the Kinase-on and Kinase-Off Signaling States in the Aer HAMP Domain. J Bacteriol 193:4095-4103.
- Campbell AJ, Watts KJ, Johnson MS, and Taylor BL. 2011. Role of the F1 region in the Escherichia coli aerotaxis receptor Aer. J Bacteriol 193:358-66.
- Watts KJ, Taylor BL, and Johnson MS. 2011. PAS/poly-HAMP signalling in Aer-2, a soluble haem-based sensor. Mol Microbiol 79:686-99.
- Campbell AJ, Watts KJ, Johnson MJ, and Taylor, BL. 2010. Gain-of-function mutations cluster in distinct regions associated with the signaling pathway in the PAS domain of the aerotaxis receptor Aer. Mol Microbiol. 77(3):575-86.
- Airola MV, Watts KJ, and Crane BR. 2010. Identifying divergent HAMP domains and poly-HAMP chains. J Biol Chem. 285(23):le7.
- Airola MV, Watts KJ, Bilwes AM, and Crane BR. 2010. Structure of concatenated HAMP domains provides a mechanism for signal transduction. Structure. 18(4):436-48.
- Watts KJ, Johnson MS, and Taylor BL. 2008. Structure-function relationships in the HAMP and proximal signaling domains of the aerotaxis receptor Aer. J Bacteriol. 190(6):2118-27.
- Taylor BL, Watts KJ, and Johnson MS. 2007. Oxygen and redox sensing by two-component systems that regulate behavioral responses: Behavioral assays and structural studies of Aer using in vivo disulfide crosslinking. In Crane B, Crane AB, and Simon M (ed.). Methods in Enzymology, Two-Component Systems, 422:190-232.
- Watts KJ, Johnson MS, and Taylor BL. 2006. Minimal requirements for oxygen sensing by the aerotaxis receptor Aer. Mol Microbiol. 59(4):1317-26.
- Watts KJ, Sommer K, Fry SL, Johnson MS, and Taylor BL. 2006. Function of the N-terminal cap of the PAS domain in signaling by the aerotaxis receptor Aer. J Bacteriol. 188(6):2154-62. Erratum in: J Bacteriol. 188(9):3429.
- Watts KJ, Ma Q, Johnson MS, and Taylor BL. 2004. Interactions between the PAS and HAMP domains of the Escherichia coli aerotaxis receptor Aer. J Bacteriol. 186:7440-7449.
- Taylor BL, Johnson MS, and Watts KJ. 2003. Signal transduction in Prokaryotic PAS Domains, pp 17-50 In ST. Crews (ed.), PAS Proteins: Regulators and Sensors of Development and Physiology. Kluwer Academic Publishers, Norwell, MA.
- Yu HS, Saw JH, Hou S, Larsen RW, Watts KJ, Johnson MS, Zimmer MA, Ordal GW, Taylor BL, and Alam M. 2002. Aerotactic responses in bacteria to photoreleased oxygen. FEMS Microbiol Lett. 217(2):237-242.
- Watts KJ, Thompson CH, Cossart YE, and Rose BR. 2002. Sequence variation and physical state of human papillomavirus type 16 cervical cancer isolates from Australia and New Caledonia. Int J Cancer. 97(6):868-874.
- Watts KJ, Thompson CH, Cossart YE, and Rose BR. 2001. Variable oncogene promoter activity of human papillomavirus type 16 cervical cancer isolates from Australia. J Clin Microbiology. 39(5):2009-2014.