Research in my laboratory seeks to address the question of what large macromolecular complexes exist inside cells and how their function is determined by their structure and location. To accomplish this goal, we use electron cryotomography (ECT) to image native cellular structures in 3D inside intact cells, carrying out structural biology in vivo. Projects in the lab fall into three categories: microbial cell biology, structural biology of HIV, and cryo-EM methods development. The HIV work is complementary to our other projects in that it drives and is driven by the same technology development, but it is funded separately. In microbial cell biology, in the next five years we aim to advance our understanding of: (1) the architectures and relationships of bacterial secretion systems; (2) the mechanisms of cell division across all three kingdoms of life; and (3) the bacterial cytoskeleton and DNA-segregating filaments. Driving these projects, in cryo-EM methods development, we aim to: (1) expand the throughput and automation of ECT; (2) apply cryogenic focused ion beam-milling to expand the reach of ECT to any cell, regardless of size; and (3) use our ECT measurements to inform the development of realistic coarse-grained models of biological processes to develop and test mechanistic hypotheses.

Public Health Relevance

Pathogenic bacteria have a devastating effect on public health, but we still lack a detailed understanding of the macromolecular machines that drive infection and disease. In the proposed work, we will use electron cryotomography to reveal the molecular details of several aspects of bacterial cell biology, potentially informing future development of therapeutic agents.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Unknown (R35)
Project #
5R35GM122588-02
Application #
9474647
Study Section
Special Emphasis Panel (ZGM1)
Program Officer
Deatherage, James F
Project Start
2017-06-01
Project End
2022-05-31
Budget Start
2018-06-01
Budget End
2019-05-31
Support Year
2
Fiscal Year
2018
Total Cost
Indirect Cost
Name
California Institute of Technology
Department
Type
Schools of Arts and Sciences
DUNS #
009584210
City
Pasadena
State
CA
Country
United States
Zip Code
91125
Mahinthichaichan, Paween; Morris, Dylan M; Wang, Yi et al. (2018) Selective Permeability of Carboxysome Shell Pores to Anionic Molecules. J Phys Chem B 122:9110-9118
Ortega, Davi R; Zhulin, Igor B (2018) Phylogenetic and Protein Sequence Analysis of Bacterial Chemoreceptors. Methods Mol Biol 1729:373-385
Ruhe, Zachary C; Subramanian, Poorna; Song, Kiho et al. (2018) Programmed Secretion Arrest and Receptor-Triggered Toxin Export during Antibacterial Contact-Dependent Growth Inhibition. Cell 175:921-933.e14
Nguyen, Lam T; Swulius, Matthew T; Aich, Samya et al. (2018) Coarse-grained simulations of actomyosin rings point to a nodeless model involving both unipolar and bipolar myosins. Mol Biol Cell 29:1318-1331
Swulius, Matthew T; Nguyen, Lam T; Ladinsky, Mark S et al. (2018) Structure of the fission yeast actomyosin ring during constriction. Proc Natl Acad Sci U S A 115:E1455-E1464
Meier, Elizabeth L; Daitch, Allison K; Yao, Qing et al. (2017) FtsEX-mediated regulation of the final stages of cell division reveals morphogenetic plasticity in Caulobacter crescentus. PLoS Genet 13:e1006999
Ortega, Davi R; Fleetwood, Aaron D; Krell, Tino et al. (2017) Assigning chemoreceptors to chemosensory pathways in Pseudomonas aeruginosa. Proc Natl Acad Sci U S A 114:12809-12814