Department of Chemistry

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W. Seth Childers

Associate Professor

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Chevron Science Center, Room 801
219 Parkman Avenue

Pittsburgh, PA 15260
412-624-3058

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Research Overview

An intriguing question with roots in the origin of life is how matter transitioned from Darwin’s warm pond to the last universal common ancestor. Impossible to address directly, scientists can still provide insights into these issues by asking questions about life today. For example, how do the simplest modern cells orchestrate the location and activity of millions of molecules like organized nano-sized factories? And how do molecules work as systems make complex decisions? Understanding these questions can also advance the design of intelligent materials, new synthetic biology technologies for health applications, and reveal antibiotic targets. Since establishing my independent career at the University of Pittsburgh in 2015, has investigated biomolecular condensates as a compartmentalization strategy in bacteria, biomolecular condensates as a  reaction crucible in the origins of life and the design of intelligent nanomaterials.  In addition, we develop synthetic biology tools and biosensors to study bacterial signaling mechanisms in how bacterial cells develop and how they impact the gut-brain axis. To investigate these questions, we apply interdisciplinary approaches that include synthetic biology, biophysical chemistry, chemical biology, mechanistic biochemistry and microbial genetics.  

The Childers Lab is currently accepting new graduate students.

Biomolecular condensates as compartments in bacteria

Figure 1: Revealing a more organized bacterial cytoplasm than the classic text book description – bacteria as a “bag of biomolecular condensates”.   

 

Recently in eukaryotes, a new type of “membraneless organelles” formed from liquid-liquid phase separation of scaffolding proteins has been realized as a fundamental way eukaryotes organize biochemistry. In fact, in the 1920s, Alexander Oparin postulated that similar coacervate assemblies were critical precursors to the first cells. However, before 2015, “membraneless organelles” were curiously absent in the bacterial kingdom. If membraneless organelles were abundant in all kingdoms of life, that would strengthen the potential role of these compartments in life’s beginnings. Moreover, it would radically change our view of bacteria that notably lack typical membrane-bound organelles.

 

Sparked by this curiosity, our lab co-discovered that biomolecular condensates organize and regulate global RNA decay and signaling pathways in bacteria. We’ve also found biomolecular condensates chemical environment uniquely stimulates the ribonuclease functions of PNPase and the kinase-to-phosphatase activity switch of the histidine kinase PleC. These findings are significant in showing that biomolecular condensates act as a compartmentalization strategy in bacteria. Critically, we  have developed a new FRET biosensor approach that reported how biomolecular condensates impact signaling enzymes in vivo. Motivated by the roles of biomolecular condensates in physiology, our lab identified an inhibitor to disrupt the phase separation of an essential bacterial protein. Combined with contemporaneous discoveries from peers, these results suggest phase separation as a fundamental way bacteria organize biochemistry into organelle-like structures—a cytoplasm more organized than the classic textbook view.  Moreover, these assemblies present new antibiotic targets.  

Development of bacterial synthetic biology tools for signaling proteins and biomolecular condensates

Figure 2: Development of Synthetic Biology Tools for signal transduction and compartmentalization in bacterial.  New tools opened the door to decode bacterial , study essential genes, optimize metabolic engineering, and sequester metals.

We also aim to translate our discovered knowledge into synthetic biology tools that can be applied to address health challenges (Figure 2). We are actively building tools that will allow us to understand how gut microbial signaling and metabolism contribute to conditions ranging from Crohn’s Disease to depression. This includes new protein engineering strategies that will help unlock the functions of cryptic signaling proteins and catalytically dead pseudokinases that control development, pathogenesis, and gut-brain-axis dysregulation. We are also developing methods that will ultimately allow us to sense and potentially one-day correct dysregulation within the gut microbiome that leads to mental health diseases. Towards these goals, we have developed biosensors to detect microbially produced indole metabolites that impact mental health. We have also repurposed peptide nanomaterials as synthetic membraneless organelles that we aim to use to produce therapeutic metabolites and proteins. These synthetic biology advances lay the foundation for studying aspects of the gut-brain axis involved in mental health issues.

Awards

  • Jane Coffin Childs Postdoctoral Fellowship (JCCF) (2011-2014) 
  • Distinguished Dissertation Award Finalist, Council of Graduate Schools/Proquest  (2011)
  • Charles T. Lester Award, Emory University (2010)
  • Microscopy Society of America (MSA) Presidential Student Award (2008) 
  • Achievement Awards for College Scientists (ARCS) Scholar Fellowship (2008-2009)
  • HHMI ORDER (On Recent Discoveries of Emory Researchers) Teaching Scholar (2007) 
  • Osbourne R. Quayle Fellowship (2007)

Publications

“The BR-body proteome contains a complex network of protein-protein and protein-RNA interactions,” Nandana, V., Rathnayaka-Mudiyanselage, I. W., Muthunayake, N. S., Hatami, A., Mousseau, C. B., Ortiz-Rodriguez, L. A., Vaishnav, J., Collins M., Gega, A., Mallikaarachchi, K. S., Yassine. H., Ghosh, A., Biteen, J. S., Zhu, Y., Champion, M. M., Childers, W. S., Schrader, J. M. Cell Reports 2023, 42, 113229
“RNase E biomolecular condensates stimulate PNPase activity,” Collins, M. J., Tomares, D. T., Nandana, V., Schrader, J. M., Childers, W. S. Sci Rep 2023, 13, 12937
“Scaffold-Scaffold Interaction Facilitates Cell Polarity Development in Caulobacter crescentus,” Lu, N., Duvall, S. W., Zhao, G., Kowallis, K. A., Zhang, C., Tan, W., Sun, J., Petitjean, H. N., Tomares, D. T., Zhao, G., Childers, W. S., Zhao, W. MBio 2023, 14
“The Future Potential of Biosensors to Investigate the Gut-Brain Axis,” Wang, J., Childers, W. S.* Front. Bioeng. Biotechnol. 2022, 9, 826479
“Phase separation modulates the assembly and dynamics of a scaffold-signaling hub in cell polarity development ,” Tan, W., Cheng, S., Li. Y., Lu, N., Sun, J.,  Tang, G., Yang, Y., Cai, K., Li, X., Ou, X., Gao, X., Zhan, G., Childers, W.S., Zhao, W In Review 2022, online
“Repurposing Peptide Nanomaterials as synthetic biomolecular condensates,” Tomares, D.T., Whitlock, S., Mann, M., Childers, W.S. ACS Synthetic Biology 2022
“Chapter Ten - Protein engineering strategies to stimulate the functions of bacterial pseudokinases,” Yang, X., Kowallis, K. A., and Childers, W. S. In Methods in Enzymology 2022, 275-302
“Regulation of the activity of the bacterial histidine kinase PleC by the scaffolding protein PodJ.,” Zhang, C., Zhao, W., Duvall, S. W., Kowallis, K. A., and Childers, W. S. The Journal of biological chemistry 2022, 298, 101683
“The upcycled roles of pseudoenzymes in two-component signal transduction,” Collins, M. J., and Childers, W. S. Current opinion in microbiology 2021, 61, 82-90
“A Biosensor for Detection of Indole Metabolites,” Wang, J., Zhang, C., and Childers, W. S. ACS synthetic biology 2021, 10, 1605-1614
“ Manipulation of Bacterial Signaling Using Engineered Histidine Kinases,” Kowallis, K. A., Duvall, S. W., Zhao, W., and Childers, W. S. Methods Mol Biol 2020, 2077, 141-163
“BR-Bodies Provide Selectively Permeable Condensates that Stimulate mRNA Decay and Prevent Release of Decay Intermediates,” Al-Husini, N., Tomares, D. T., Pfaffenberger, Z. J., Muthunayake, N. S., Samad, M. A., Zuo, T., Bitar, O., Aretakis, J. R., Bharmal, M. M., Gega, A., Biteen, J. S., Childers, W. S., and Schrader, J. M. Molecular cell 2020, 78, 670-682.e678
“Phase-separated bacterial ribonucleoprotein bodies organize mRNA decay,” Muthunayake, N. S., Tomares, D. T., Childers, W. S., and Schrader, J. M. Wiley interdisciplinary reviews. RNA 2020, e1599
“Synthetic Control of Signal Flow Within a Bacterial Multi-Kinase Network,” Kowallis, K. A., Silfani, E. M., Kasumu, A. P., Rong, G., So, V., and Childers, W. S. ACS synthetic biology 2020, 9, 1705-1713
“α-Proteobacterial RNA Degradosomes Assemble Liquid-Liquid Phase-Separated RNP Bodies,” Nadra Al-Husini, Dylan T. Tomares, Obaidah Bitar, W. Seth Childers, & Jared M. Schrader Molecular Cell 2018
“Cell Fate Regulation Governed by a Repurposed Bacterial Histidine Kinase,” Childers, W.S., Xu, Q., Mann, T.H., Irimpan I.M., Blair, J.A., Deacon, A.M., Shapiro L. PLOS Biology 2014
“Branched Signal Wiring of an Essential Bacterial Cell-Cycle Phosphotransfer Protein,” Blair, J.A.*, Xu, Q.*, Childers, W.S.*, Irimpan I.M, Kern J.W., Eckart M. Deacon, A.M., Shapiro L. Structure 2013, 21, 1590-1601
“Phase Networks of Cross-β assemblies,” Childers, W.S., Anthony, N.R., Berland, K.M., Mehta, A.K. & Lynn, D.G. Langmuir 2012, 28, 6386-6395
“Remodeling Cross-β Nanotube Surfaces with Peptide/Lipid Chimeras,” Ni, R., Childers, W.S., Hardcastle, K.I., Mehta, A.K. & Lynn, D.G. Angewandte Chemie Int Ed. 2012, 124, 6739-6742