A5032467861- Microtubule and mitosis dynamics
- Micro and Nano Robotics
- Reproductive Biology and Fertility
- Cellular Mechanics and Interactions
- Photosynthetic Processes and Mechanisms
- Mitochondrial Function and Pathology
- Genomics and Chromatin Dynamics
- Advanced Fluorescence Microscopy Techniques
- Nuclear Structure and Function
- Advanced Thermodynamics and Statistical Mechanics
- Lipid Membrane Structure and Behavior
- Plant Molecular Biology Research
- Protist diversity and phylogeny
- Advanced Materials and Mechanics
- Protein Structure and Dynamics
- Ovarian function and disorders
- Cellular transport and secretion
- Molecular Biology Techniques and Applications
- Assisted Reproductive Technology and Twin Pregnancy
- Genetics, Aging, and Longevity in Model Organisms
- Prenatal Screening and Diagnostics
- Supramolecular Self-Assembly in Materials
- Bacteriophages and microbial interactions
- Adipose Tissue and Metabolism
- Spaceflight effects on biology
Harvard University Press
2009-2025
Harvard University
2015-2024
Flatiron Institute
2020-2024
Flatiron Health (United States)
2020-2024
Simons Foundation
2021-2023
University of Virginia
2021
Center for Systems Biology
2010-2019
RELX Group (Netherlands)
2017
RELX Group (United States)
2017
University of California, Santa Barbara
2003-2014
Excitons in semiconductors, bound pairs of excited electrons and holes, can form the basis for new classes quantum optoelectronic devices. A van der Waals heterostructure built from atomically thin semiconducting transition metal dichalcogenides (TMDs) enables formation excitons holes distinct layers, producing interlayer with large binding energy a long lifetime. Employing heterostructures monolayer TMDs, we realize optical electrical generation long-lived neutral charged excitons. We...
Cellular factors tightly regulate the architecture of bundles filamentous cytoskeletal proteins, giving rise to assemblies with distinct morphologies and physical properties, a similar control supramolecular organization nanotubes nanorods in synthetic materials is highly desirable. However, it unknown what principles determine how macromolecular interactions lead defined morphologies. In particular, electrostatic between charged polyelectrolytes, which are ubiquitous biological...
SummarySpindles are arrays of microtubules that segregate chromosomes during cell division. It has been difficult to validate models spindle assembly due a lack information on the organization in these structures. Here we present method, based femtosecond laser ablation, capable measuring detailed architecture spindles. We used this method study metaphase Xenopus laevis egg extracts and found shortest near poles become progressively longer toward center spindle. These data, combination with...
Significance The spindle segregates chromosomes during cell division and is composed of microtubules hundreds other proteins, but the manner in which these molecular constituents self-organize to form remains unclear. Here we use a holistic approach, based on quantitative measurements spindles spatiotemporal correlation functions microtubule density, orientation, stresses, identify key processes responsible for self-organization. We show that turnover collective effects local interactions,...
How lipopolysaccharides bridge the gap The outer membrane of Gram-negative bacteria is composed lipopolysaccharide, a large glycolipid that prevents drugs from entering cells. Disrupting lipopolysaccharide assembly hypersensitizes to antibiotics. Sherman et al. used biochemical tools observe transport. Seven proteins, which are conserved in all bacteria, appear form protein uses adenosine triphosphate power transport one another. ability monitor intermembrane will help efforts develop and...
Many cellular processes are driven by cytoskeletal assemblies. It remains unclear how filaments and motor proteins organize into scale structures molecular properties of components affect the large-scale behaviors these systems. Here, we investigate self-organization stabilized microtubules in Xenopus oocyte extracts find that they can form macroscopic networks spontaneously contract. We propose contractions clustering microtubule minus ends dynein. Based on this idea, construct an active...
Understanding the coordination of cell-division timing is one outstanding questions in field developmental biology. One active control parameter cell-cycle duration temperature, as it can accelerate or decelerate rate biochemical reactions. However, controlled experiments at cellular scale are challenging, due to limited availability biocompatible temperature sensors, well lack practical methods systematically local temperatures and dynamics. Here, we demonstrate a method probe...
Cells are the basic units of all living matter which harness flow energy to drive processes life. While biochemical networks involved in transduction well-characterized, energetic costs and constraints for specific cellular remain largely unknown. In particular, what budgets cells? What limits flows impose on processes? Do cells operate near these limits, if so how do impact functions? Physics has provided many tools study nonequilibrium systems define physical but applying cell biology...
During cell division, kinetochore microtubules (KMTs) provide a physical linkage between the chromosomes and rest of spindle. KMTs in mammalian cells are organized into bundles, so-called kinetochore-fibers (k-fibers), but ultrastructure these fibers is currently not well characterized. Here, we show by large-scale electron tomography that each k-fiber HeLa metaphase composed approximately nine KMTs, only half which reach spindle pole. Our comprehensive reconstructions allowed us to analyze...
Cytoplasmic dynein-1 is a minus-end-directed motor protein that transports cargo over long distances and organizes the intracellular microtubule (MT) network. How dynein activity harnessed for these diverse functions remains unknown. Here, we have uncovered mechanism how processive dynein-dynactin complexes drive MT-MT sliding, reorganization, focusing, activities required mitotic spindle assembly. We find motors cooperatively accumulate, in limited numbers, at MT minus-ends. Minus-end...
Spindle microtubules, whose dynamics vary over time and at different locations, cooperatively drive chromosome segregation. Measurements of microtubule spindle ultrastructure can provide insight into the behaviors helping elucidate mechanism Much work has focused on organization kinetochore that is, region between chromosomes poles. In comparison, microtubules in central-spindle region, segregating chromosomes, have been less thoroughly characterized. Here, we report measurements movement...
The proper positioning of mitotic spindle in the single-cell
Significance How nanometer-sized proteins produce micron-scale subcellular organization is poorly understood. Here we study the spatial of ras-related nuclear protein (Ran) pathway in mitosis. Our results reveal that whereas upstream components this are well described as a reaction-diffusion system downstream exhibit more complex behaviors which their association with microtubules causes them to be enriched spindle region. Because Ran influences nucleation microtubules, suggests presence...
Proper kinetochore-microtubule attachments, mediated by the NDC80 complex, are required for error-free chromosome segregation. Erroneous attachments corrected tension dependence of interactions. Here, we present a method, based on fluorescence lifetime imaging microscopy and Förster resonance energy transfer, to quantitatively measure fraction complexes bound microtubules at individual kinetochores in living human cells. We found that binding is modulated autonomous fashion over prometaphase...
Six transmembrane segments, S1–S6, cluster around the central pore-forming region in voltage-gated K+ channels. To investigate structural characteristics of S2 segment Shaker channel, we replaced each residue singly with tryptophan (or alanine for native tryptophan). All but one 23 Trp mutants expressed voltage-dependent currents Xenopus oocytes. The effects mutations were classified as being low or high impact on channel gating properties. periodicity evident these supports an α-helical...
Microtubules are hollow cylinders composed of tubulin heterodimers that stack into linear protofilaments interact laterally to form the microtubule wall. Synchrotron x-ray diffraction microtubules under increasing osmotic stress shows they transition rectangular bundles with noncircular buckled cross sections, followed by hexagonally packed bundles. This new technique probes strength interprotofilamen bonds, yielding insight mechanism which associated proteins and chemotherapy drug taxol...
Intermolecular interactions between charged membranes and biological polyelectrolytes, tuned by physical parameters, which include the membrane charge density bending rigidity, spontaneous curvature, biopolymer overall of complex, lead to distinct structures morphologies. The self-assembly cationic liposome–microtubule (MT) complexes was studied, using synchrotron x-ray scattering electron microscopy. Vesicles were found either adsorb onto MTs, forming a “beads on rod” structure, or undergo...