The separation of yolk from the embryonic cytoplasm characterizes the initial phase of embryonic development in oviparous animals, including fish, frogs and flies. While yolk-cytoplasm separation is known for allocation of energy resources and partitioning of maternally deposited patterning elements critical for cell fate specification, it remains unknown whether such separation changes the...
The interplay between inside-out and outside-in activation of integrin receptor orchestrates cell motility and tissue regeneration. While such mechanisms of RGD-binding integrin, including integrin beta1 and beta3, are well documented, mechano-sensitive regulations of integrin beta6 remain largely unknown. Using the viscous RGD-membrane as the model system, we find that integrin beta6 and...
Elastic tissues such as arteries and tendons have dense extracellular matrices with wavy structures that allow high strain. The resident cells follow the wavy structures that change with load, disease, and aging. Few studies, however, study the impacts of this wavy morphology on cell behavior and mechanotransduction. Using microfabrication techniques, we precisely control single cell shape and...
Cell membranes serve as a central platform to host a variety of proteins essential for cellular activities such as cell signaling, morphogenesis, and membrane trafficking. At the same time, the membranes also undergo drastic morphological changes in a number of essential processes, such as endocytosis, intracellular trafficking, and cytokinesis, etc. An intriguing yet challenging question to...
We have worked on the influence of matrix stiffness on cellular physiology in epithelial cells and fibroblasts as well, which plays a very important role in pathophysiology of organ and tissue fibrosis. The current research theme of my research has been to unveil the mechanobiological mechanism of converting wound repair into regeneration. We have discovered that breaking symmetry of cell...
Detecting megadalton matrix-assisted laser desorption/ionization (MALDI) ions with linear ion trap mass spectrometer (LIT-MS) is a technical challenge. In this talk, we employ MALDI LIT- MS to successfully analyze megadalton protein, polymer, and proteasome ions. A homebuilt linear ion trap mass spectrometer (LIT-MS) equipped with a charge sensing particle detector (CSPD) is used for high mass...
Large-scale cell death is widely observed during embryonic development and various human pathological conditions. However, a systems-level understanding for how large-scale cell death emerges had been lacking. Harnessing time-lapse imaging, chemical/genetic perturbations and mathematical modeling, we show how metabolic stress quantitatively modulate cellular state for the emergence of redox...
Most animals have systematic left-right asymmetry in their bodies and organs. Their chiral property should be originated from the organization of the chirality of their constituents. However, the mechanisms of how chiral information is brought from the molecular to the cell, tissue and organ scales are largely unresolved. In my talk, I will present our recent study combining experiment and...
Advancements in interferometric scattering microscopy (iSCAT) enable label-free detection of nanoscale structures and dynamics with high sensitivity and fast acquisition rates. This technology overcomes fluorescence imaging limitations, such as photobleaching, facilitating long-term or high-speed measurements. However, analyzing label-free signals to extract specific target information remains...
Endoplasmic reticulum (ER)-mitochondrial junctions (EMJs) reduce intracellular Ca2+ storage by suppressing store-operated Ca2+ entry (SOCE)
The organization and dynamics of chromatin is essential for the regulation of gene expression. Transcription factors (TFs) regulate gene expression by binding to specific consensus motifs within enhancers or promoter-proximal regions. The mechanism by which TFs bind to their cognate chromatin targets within a complex nuclear environment to assemble transcriptional machinery at specific genomic...
The activation of integrins and the subsequent formation of focal complexes is a critical function in cellular sensing of ECM substrates and cell migration. Integrin adhesion complexes (IACs) allow for cell adhesion, transduce force, and signal through several pathways. While much work has been done to uncover the components and regulators involved in adhesion formation and dynamics, we have...
The study of chromatin nanostructures in living cells is complex due to their constant motion. In this talk, I will introduce a novel correlation spectroscopy approach using interferometric scattering (iSCAT) microscopy, which allows for the spatial mapping of chromatin configurations and dynamics in live, unlabeled cell nuclei. This innovative label-free method detects linear scattering...
"Replication-dependent histone (Repli-Histo) labeling specifically visualizes physical properties of euchromatin/heterochromatin in living human cells.
Katsuhiko Minami1, 2, Satoru Ide1, 2, Sachiko Tamura1, and Kazuhiro Maeshima1, 2
1 Genome Dynamics Laboratory, National Institute of Genetics
2 Graduate Institute for Advanced Studies, SOKENDAI
Abstract
Recent advanced imaging studies...
Microtubules are hollow cylindrical cytoskeletal polymers of laterally associated protofilaments that contain head-to-tail aligned ɑ/β-tubulin heterodimers. While the exposed exterior is within reach for proteins, the mechanism regulating the accessibility of the confined micrometer-long microtubule lumen for the long-observed luminal particles remains unknown. Here, we employed structural...
Differentiated cardiomyocytes (CMs) must undergo diverse morphological and functional changes during postnatal development. However, the initiation and coordination of these processes remain unclear. We reveal an integrated, time-ordered transcriptional network that begins with expression of genes for cell-cell connections and leads to a sequence of structural, cell cycle, functional, and...
Physical spacing of chromatin is critical in regulating bio-chemical and transcriptional abilities of genes, and proper functionality of the genomic content depends on the nonrandom organization of chromatin. Meanwhile, in a living cell, other subnuclear molecules, such as enzymes like polymerase and topoisomerase, act to facilitate cellular functions. Mechanical perturbation due to actions of...
In Nature, many dynamic processes take place in purely aqueous environments within relatively narrow range of environmental conditions, such as temperature. How such sophisticated processes across hierarchical lengthscales in the natural biological world remains fascinating to materials scientists. One of the key phenomena that drives the formation of a diverse range of structures is aqueous...
Biological membranes undergo dynamic remodeling that is essential for cellular homeostasis. BAR protein SNX9 is known to play a key role in actin-driven membrane remodeling, for example at saddle-shaped or tubular membrane necks connecting vesicular buds to the plasma membrane during endocytosis, and in the more complex membrane remodeling of membrane ruffling during macropinocytosis. SNX9 has...
This study delves into the molecular dynamics that underpin critical biological processes in neurodegeneration. We use molecular dynamics simulations to investigate the interactions of Abeta42 monomers with fibrillar surfaces, a pivotal factor in Alzheimer's disease progression. Employing coarse-grained simulations, we focus on the diffusion behaviors of freely diffusing Abeta42 monomers...
Membrane curvature in the range of tens to hundreds of nanometers is involved in many essential cellular processes. Membrane curvatures in living cells are often below optical resolution and are highly dynamic, making it a technical challenge to explore curvature-initiated signaling events. We use nanofabrication to engineer vertical nanostructures to precisely manipulate the location, degree,...
The diffusion of tracer particles within a polymer environment is a promising topic connected with numerous biological and industrial applications, including intracellular macromolecule transport and nanoparticle diffusion. Despite extensive studies, the study of self-propelled particles within a polymer network has received attention recently and poorly understood. Here we study the...
In this work, we address the participation of primary and secondary “Carotenoids” in the life activity of the regenerating anterior region of A. viride. A. viride is tasked with building entire body segments out of their single starting cell at their amputated region and undergoing epimorphic regeneration, therefore, these annelids are the most suitable for the study of regeneration. In...
"Conventionally, mammalian cells are cultured on stiff plastic or glass dishes. This is because cells have intrinsic contractility and exert mechanical forces to their substrates. It is critical for the cells to receive sufficient mechanical feedback, therefore stiff materials have been chosen for the cell culturing scaffolds, otherwise the cells undergo apoptosis, cellular suicide. On the...
