Mechthild Pohlschroder

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Contact information
201 Leidy Labs
415 University Avenue
Philadelphia, PA 19104-6018
Office: 215 573-2283
Fax: 215 898-8780
Vordiplom (Biology)
University of Muenster, Germany, 1989.
PhD (Microbiology)
University of Massachusetts, Amherst, 1994.
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Description of Research Expertise

Research Interests
Prokaryotic Cell Surface Biogenesis and Function

Key Words: biofilm, archaea, protein secretion, prokaryotes, type IV pili, flagella, sortase, exosortase, archaeosortase, twin arginine transport.

Description of Research
Description of Research

Bacteria and archaea have complex cell envelopes that have several important functions, including providing a barrier that protects the cytoplasm from the environment. Along with its associated proteinaceous structures, it also ensures cell stability, facilitates motility and mediates adherence to biotic and abiotic surfaces. Although archaea are ubiquitous, present in all habitats examined thus far, including the human microbiome, compared to the bacteria, little is yet known about this domain of life. Using the genetically and biochemically amenable model archaeon Haloferax volcanii, my lab employs well-established techniques of molecular biology, biochemistry, and microscopy, as well as cutting edge technologies, such as RNAseq, to characterize the unique archaeal, as well as the highly conserved, aspects of archaeal cell surface biology.

Our lab’s extensive characterization of the evolutionarily conserved Sec pathway, as well as the Tat pathway, advanced the understanding of protein transport across both domains of prokaryotes. Exciting results from our recent analyses of cell surface anchoring strategies of archaeal proteins have uncovered a seemingly unique archaeal surface anchoring strategy and also revealed a novel membrane anchoring mechanism that is conserved between archaea and bacteria. Furthermore, our analyses of archaeal surface filaments led to the identification of previously unknown roles of type IV pilins in the regulation of early steps in biofilm formation (Fig. 1). The lab has used the data gleaned from these in vivo studies to develop novel software programs, as well as to improve existing ones, that predict the substrates that use specific transport and cell surface anchoring pathways. Information gleaned from these studies has invariably been used to further develop our understanding of the molecular mechanisms

Rotation Projects
1. Characterization of H. volcanii cell surface anchoring mechanisms.

2. Genetic screens using transposon mutagenesis to identify components involved in processes such as surface adhesion, exopolysaccharide biosynthesis and motility.

3. Analysis of novel type IV pili functions

Lab Personnel:
Farid Abdul, Postdoctoral Associate
Stefan Schulze, Postdoctoral Associate
Ronald Rodriguez, Post-Baccalaureate Student
Georgio Legerme, Research Assistant
Aime Bienfait Iriganeza, Undergraduate Student
Gregory Whitehorn, Undergraduate Student

Selected Publications:
1. Halim, MFA, J. Stolzfus, S. Schulze, M. Hippler and M. Pohlschroder. 2016. ArtA-dependent processing of a Tat containing a conserved tripartite structure that is not localized at the C-terminus. J. Bacteriol. Submitted.
2. Kouassi J.E., Waldron I, Tripepi, M and M. Pohlschroder. 2017. Laboratory Activity to Promote Student Understanding of UV Mutagenesis and DNA Repair. JMBE. doi:10.1128/jmbe.v18i1.1202.
3. Legerme G., E. Yang, R. Esquivel, S. Kiljunan, H. Savilathi and M. Pohlschroder. 2016. Screening of a Haloferax volcanii transposon library reveals novel motility and adhesion mutants. Life.6:1-14.
4. Halim, F., K. Karch, Y. Zhou, B. Garcia and M. Pohlschroder. 2016. Permuting the PGF-CTERM signature motif blocks both archaeosortase-dependent C-terminal cleavage and prenyl lipid attachment for the Haloferax volcanii S-layer glycoprotein. J. Bacteriol. 198:808-815.
5. Esquivel, R., S. Schulze, M. Hippler and M. Pohlschroder. 2016. Identification of Haloferax volcanii flagellin and pilin N-glycans with diverse roles. J. Biol. Chem. 291:10602-14.
6. Pohlschroder, M. and S. Albers. 2016. Editorial: Archaeal cell envelope and surface structures. Front. Microbiol. 6:1515.
7. Pohlschroder, M. and R. Esquivel. 2015. Archaeal type IV pili and their roles in biofilm formation. Frontiers in Microbiology (invited review).6:190.
8. Kiljunen, S., M. Pujunen, K. Dilks, S. Storf, M. Pohlschroder and H. Savilahti. 2014. Generation of comprehensive transposon insertion mutant library for the model archaeon, Haloferax volcanii, and its use for gene discovery. BMC Biol. 103.
9. Esquivel R. and M. Pohlschroder. 2014. A conserved type IV pilin signal peptide H-domain is critical for the post-translational regulation of flagella-dependent motility. Mol. Microbiol. 93:493-504.
10. Esquivel, R, R. Xu and M. Pohlschroder. 2013. Novel, archaeal adhesion pilins with a conserved N-terminus. J. Bacteriol. 195:3808-3818.
11. Abdul Halim, M. F, F. Pfeiffer, J. Zou, A. Frisch, D. Haft, S. Wu, N. Tolic, H. Brewer, S. H. Payne, L. Paša-Tolic, and M Pohlschroder. 2013. Haloferax volcanii archaeosortase is required for motility, mating and C-terminal processing of the S-layer glycoprotein. Mol. Microbiol. 85:1164-1175.
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Last updated: 06/23/2017
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