Joshua W. Shaevitz

Contact
shaevitz@princeton.eduResearch Area
Biochemistry, Biophysics & Structural BiologyResearch Focus
Cellular and molecular biophysics; shape, mechanics and motilityThe cells that make up all living organisms come in a dizzying array of sizes and shapes, each with unique structural and mechanical properties. When many cells move they contort their bodies to glide along surfaces or swim through fluid. We are interested in the different physical strategies that mother nature has found to create the cellular and sub-cellular structures that perform these amazing feats.
One of the species we study, Spiroplasma melliferum, is a helix barely more than 100 nm across and a few microns long. How does this cell achieve its beautiful shape? When these cells swim they change the helicity of their entire bodies to produce movement. How does this work? How can a cell organize its contents in such a tightly packed space?
It was recently discovered that many, if not all, bacteria use an internal cytoskelton to define their shape, to guide intracellular organization and to produce movement. Our lab studies physical aspects of the prokaryotic cytoskeleton. What are the structural properties of the individual cytoskeletal filaments and how do they contribute to overall cell mechanics? Is mechanical stress induced by the cytoskeleton used to determine cell shape? Are these filaments used as tracks by molecular motors as they are in eukaryotes by kinesin and myosin? These are just some of the basic questions that our lab is interested in.
For this research, we are developing new instrumentation that combines mechanical perturbation of cells and molecules with visualization of key protein and macromolecular structures. Our toolbox includes unique combinations of optical microscopy, fluorescence and deconvolution microscopy, optical trapping, atomic force microscopy, as well as biophysical modeling and simulation.
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Multicolor multifocal 3D microscopy using in-situ optimization of a spatial light modulator. Sci Rep. 2022 ;12(1):16343. .
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Capillary forces generated by biomolecular condensates. Nature. 2022 ;609(7926):255-264. .
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Subcellular localization of type IV pili regulates bacterial multicellular development. Nat Commun. 2022 ;13(1):6334. .
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distinguishes surfaces by stiffness using retraction of type IV pili. Proc Natl Acad Sci U S A. 2022 ;119(20):e2119434119. .
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Publisher Correction: SLEAP: A deep learning system for multi-animal pose tracking. Nat Methods. 2022 ;19(5):628. .
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Deep phenotyping reveals movement phenotypes in mouse neurodevelopmental models. Mol Autism. 2022 ;13(1):12. .
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Isolation disrupts social interactions and destabilizes brain development in bumblebees. Curr Biol. 2022 ;32(12):2754-2764.e5. .
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Measuring the repertoire of age-related behavioral changes in Drosophila melanogaster. PLoS Comput Biol. 2022 ;18(2):e1009867. .
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SLEAP: A deep learning system for multi-animal pose tracking. Nat Methods. 2022 ;19(4):486-495. .
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Art Ashkin and the Origins of Optical Trapping and Particle Manipulation. Methods Mol Biol. 2022 ;2478:11-22. .
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Acinetobacter baylyi regulates type IV pilus synthesis by employing two extension motors and a motor protein inhibitor. Nat Commun. 2021 ;12(1):3744. .
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Decoding locomotion from population neural activity in moving . Elife. 2021 ;10. .
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Low-Reynolds-number, biflagellated Quincke swimmers with multiple forms of motion. Proc Natl Acad Sci U S A. 2021 ;118(29). .
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Competitive binding of independent extension and retraction motors explains the quantitative dynamics of type IV pili. Proc Natl Acad Sci U S A. 2021 ;118(8). .
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A hydrodynamic instability drives protein droplet formation on microtubules to nucleate branches. Nat Phys. 2021 ;17(4):493-498. .
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Paired fruit flies synchronize behavior: Uncovering social interactions in Drosophila melanogaster. PLoS Comput Biol. 2020 ;16(10):e1008230. .
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Quantifying behavior to understand the brain. Nat Neurosci. 2020 ;23(12):1537-1549. .
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Uniform intensity in multifocal microscopy using a spatial light modulator. PLoS One. 2020 ;15(3):e0230217. .
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Spatiotemporal organization of branched microtubule networks. Elife. 2019 ;8. .
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Self-Driven Phase Transitions Drive Myxococcus xanthus Fruiting Body Formation. Phys Rev Lett. 2019 ;122(24):248102. .
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Fast animal pose estimation using deep neural networks. Nat Methods. 2019 ;16(1):117-125. .
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Substrate-rigidity dependent migration of an idealized twitching bacterium. Soft Matter. 2019 ;15(30):6224-6236. .
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Microbiology: Peeling Back the Layers of Bacterial Envelope Mechanics. Curr Biol. 2018 ;28(20):R1210-R1211. .
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Optogenetic dissection of descending behavioral control in . Elife. 2018 ;7. .
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MreB polymers and curvature localization are enhanced by RodZ and predict E. coli's cylindrical uniformity. Nat Commun. 2018 ;9(1):2797. .
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A gated relaxation oscillator mediated by FrzX controls morphogenetic movements in Myxococcus xanthus. Nat Microbiol. 2018 ;3(8):948-959. .
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Automatically tracking neurons in a moving and deforming brain. PLoS Comput Biol. 2017 ;13(5):e1005517. .
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An unsupervised method for quantifying the behavior of paired animals. Phys Biol. 2017 ;14(1):015006. .
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Introduction to Optical Tweezers. Methods Mol Biol. 2017 ;1486:3-24. .
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The effect of antibiotics on protein diffusion in the Escherichia coli cytoplasmic membrane. PLoS One. 2017 ;12(10):e0185810. .
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MreB Orientation Correlates with Cell Diameter in Escherichia coli. Biophys J. 2016 ;111(5):1035-43. .
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Predictability and hierarchy in Drosophila behavior. Proc Natl Acad Sci U S A. 2016 ;113(42):11943-11948. .
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The PSI-U1 snRNP interaction regulates male mating behavior in Drosophila. Proc Natl Acad Sci U S A. 2016 ;113(19):5269-74. .
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ASM Journals Eliminate Impact Factor Information from Journal Websites. mSystems. 2016 ;1(4). .
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Whole-brain calcium imaging with cellular resolution in freely behaving Caenorhabditis elegans. Proc Natl Acad Sci U S A. 2016 ;113(8):E1074-81. .
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Biophysical Measurements of Bacterial Cell Shape. Methods Mol Biol. 2016 ;1440:227-45. .
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RodZ links MreB to cell wall synthesis to mediate MreB rotation and robust morphogenesis. Proc Natl Acad Sci U S A. 2015 ;112(40):12510-5. .
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Directional reversals enable Myxococcus xanthus cells to produce collective one-dimensional streams during fruiting-body formation. J R Soc Interface. 2015 ;12(109):20150049. .
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Simple Experimental Methods for Determining the Apparent Focal Shift in a Microscope System. PLoS One. 2015 ;10(8):e0134616. .
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Origins of Escherichia coli growth rate and cell shape changes at high external osmolality. Biophys J. 2014 ;107(8):1962-1969. .