A5100784937- Microtubule and mitosis dynamics
- Micro and Nano Robotics
- Protist diversity and phylogeny
- Cellular transport and secretion
- Genetic and Kidney Cyst Diseases
- Photosynthetic Processes and Mechanisms
- Cellular Mechanics and Interactions
- Cardiomyopathy and Myosin Studies
- Advanced Fluorescence Microscopy Techniques
- Advanced biosensing and bioanalysis techniques
- Telomeres, Telomerase, and Senescence
- CRISPR and Genetic Engineering
- SARS-CoV-2 and COVID-19 Research
- DNA Repair Mechanisms
- Photoreceptor and optogenetics research
- Genomics and Chromatin Dynamics
- Mitochondrial Function and Pathology
- Monoclonal and Polyclonal Antibodies Research
- Nuclear Structure and Function
- Advanced Electron Microscopy Techniques and Applications
- Bacteriophages and microbial interactions
- Force Microscopy Techniques and Applications
- ATP Synthase and ATPases Research
- RNA and protein synthesis mechanisms
- Lipid Membrane Structure and Behavior
University of California, Berkeley
2016-2025
Lawrence Berkeley National Laboratory
2022-2024
Atatürk University
2007-2023
Brigham and Women's Hospital
2022
Harvard University
2022
Berkeley College
2012-2018
University of California System
2014
University of California, San Francisco
2003-2008
Howard Hughes Medical Institute
2003-2008
United States Army Medical Command
2007
Myosin V is a dimeric molecular motor that moves processively on actin, with the center of mass moving approximately 37 nanometers for each adenosine triphosphate hydrolyzed. We have labeled myosin single fluorophore at different positions in light-chain domain and measured step size standard deviation <1.5 nanometers, 0.5-second temporal resolution, observation times minutes. The alternates between + 2x nm - 2x, where x distance along direction motion dye midpoint two heads. These results...
Kinesin is a processive motor that takes 8.3-nm center-of-mass steps along microtubules for each adenosine triphosphate hydrolyzed. Whether kinesin moves by "hand-over-hand" or an "inchworm" model has been controversial. We have labeled single head of the dimer with Cy3 fluorophore and localized position dye to within 2 nm before after step. observed heads take 17.3 +/- 3.3 nm. A kinetic analysis dwell times between shows 17-nm alternate 0-nm steps. These results strongly support...
Highly infectious illness caused by pathogens is endemic especially in developing nations where there limited laboratory infrastructure and trained personnel. Rapid point-of-care (POC) serological assays with minimal sample manipulation low cost are desired clinical practice. In this study, we report an automated POC system for Ebola RNA detection RNA-guided endonuclease Cas13a, utilizing its collateral degradation after activation. After microfluidic mixing hybridization, nonspecific...
A conformational checkpoint of Cas9 enables on-target cleavage while blocking access to the active state at off-target sites.
Abstract Imaging chromatin dynamics is crucial to understand genome organization and its role in transcriptional regulation. Recently, the RNA-guidable feature of CRISPR-Cas9 has been utilized for imaging within live cells. However, these methods are mostly applicable highly repetitive regions, whereas regions with low or no repeats remains as a challenge. To address this challenge, we design single-guide RNAs (sgRNAs) integrated up 16 MS2 binding motifs enable robust fluorescent signal...
The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection causes Disease 2019 (COVID-19), a pandemic that seriously threatens global health. SARS-CoV-2 propagates by packaging its RNA genome into membrane enclosures in host cells. of the viral nascent virion is mediated nucleocapsid (N) protein, but underlying mechanism remains unclear. Here, we show N protein forms biomolecular condensates with genomic both vitro and mammalian While spherical assemblies homopolymeric...
Microtubule (MT)-associated protein 7 (MAP7) is a required cofactor for kinesin-1-driven transport of intracellular cargoes. Using cryo-electron microscopy and single-molecule imaging, we investigated how MAP7 binds MTs facilitates kinesin-1 motility. The MT-binding domain (MTBD) bound as an extended α helix between the protofilament ridge site lateral contact. Unexpectedly, MTBD partially overlapped with binding inhibited its However, by tethering to MT, projection prevented dissociation...
Mitochondrial transport along microtubules is mediated by Miro1 and TRAK adaptors that recruit kinesin-1 dynein-dynactin. To understand how these opposing motors are regulated during mitochondrial transport, we reconstitute the bidirectional of Miro1/TRAK in vitro. We show coiled-coil domain activates dynein-dynactin enhances motility activated its cofactor MAP7. find both move towards kinesin-1's direction, whereas excluded from binding transported dynein-dynactin, avoiding motor...
We introduce the technique of FIONA, fluorescence imaging with one nanometer accuracy. This is a that able to localize position single dye within approximately 1 nm in x-y plane. It done simply by taking point spread function fluorophore excited wide field illumination and locating center fluorescent spot two-dimensional Gaussian fit. motivate development FIONA unraveling walking mechanism molecular motors myosin V, VI, kinesin. find they all walk hand-over-hand fashion.
Doing the Side Step The molecular motor, dynein, contains two ring domains responsible for its movement along microtubule. However, how rings move relative to each other during processive motility and whether dynein processivity requires interhead coordination are unclear. To directly observe “walks” microtubules, DeWitt et al. (p. 221 , published online 8 December) performed advanced fluorescence-imaging studies follow both motor of a single at nanometer resolution. data suggest that heads...
Myosin VI is a reverse direction myosin motor that, as dimer, moves processively on actin with an average center-of-mass movement of ∼30 nm for each step. We labeled single fluorophore either its domain or the distal two calmodulins (CaMs) located putative lever arm. Using technique called FIONA (fluorescence imaging one nanometer accuracy), step size was observed standard deviation <1.5 nm, 0.5-s temporal resolution, and observation times minutes. Irrespective probe position, head ∼60...
Human telomeres terminate with a single-stranded 3' G overhang, which can be recognized as DNA damage site by replication protein A (RPA). The protection of (POT1)/POT1-interacting 1 (TPP1) heterodimer binds specifically to telomeric (ssTEL) and protects overhangs against RPA binding. overhang spontaneously folds into various G-quadruplex (GQ) conformations. It remains unclear whether GQ formation affects the ability POT1/TPP1 compete access ssTEL. Using single-molecule Förster resonance...
Intraflagellar transport (IFT) is essential for the elongation and maintenance of eukaryotic cilia flagella. Due to traffic jam multiple trains at ciliary tip, how IFT are remodeled in these turnaround zones cannot be determined by conventional imaging. Using PhotoGate, we visualized full range movement single motors Chlamydomonas Anterograde split apart complexes mix with each other tip assemble retrograde trains. Dynein-1b carried kinesin-II as inactive cargo on anterograde Unlike...
The assembly and maintenance of all cilia flagella require intraflagellar transport (IFT) along the axoneme. IFT has been implicated in sensory motile ciliary functions, but mechanisms this relationship remain unclear. Here, we used Chlamydomonas flagellar surface motility (FSM) as a model to test whether provides force for gliding cells across solid surfaces. We show that trains are coupled membrane glycoproteins (FMGs) Ca(2+)-dependent manner. transiently pause through adhesion their FMG...