A5021268165- Cellular transport and secretion
- Protein Kinase Regulation and GTPase Signaling
- Cellular Mechanics and Interactions
- Microtubule and mitosis dynamics
- Ion channel regulation and function
- Neuroscience and Neuropharmacology Research
- Cancer-related Molecular Pathways
- Receptor Mechanisms and Signaling
- Advanced Fluorescence Microscopy Techniques
- Lipid Membrane Structure and Behavior
- Cell Adhesion Molecules Research
- Renal Diseases and Glomerulopathies
- Medical and Health Sciences Research
- Ion Channels and Receptors
- Endoplasmic Reticulum Stress and Disease
- Criminal Law and Policy
- Genomics and Chromatin Dynamics
- DNA Repair Mechanisms
- Ubiquitin and proteasome pathways
- Chronic Kidney Disease and Diabetes
- Renal and related cancers
- Cell Image Analysis Techniques
- RNA Interference and Gene Delivery
- Erythrocyte Function and Pathophysiology
- Gene Regulatory Network Analysis
Stanford University
2015-2024
Cornell University
2019-2024
Asklepios Klinik Barmbek
2012-2024
Semmelweis University
2024
Universität Hamburg
2005-2024
Weill Cornell Medicine
2020-2024
University Medical Center Hamburg-Eppendorf
2011-2024
Zimmerman Associates (United States)
2024
Universitätsmedizin Greifswald
2024
University of Bonn
2024
The range of messenger action a point source Ca2+ or inositol 1,4,5-trisphosphate (IP3) was determined from measurements their diffusion coefficients in cytosolic extract Xenopus laevis oocytes. coefficient (D) [3H]IP3 injected into an 283 μm2/s. D for increased 13 to 65 μm2/s when the free calcium concentration raised about 90 nM 1 μm. slow physiologic results its binding slowly mobile immobile buffers. calculated effective ranges before it is buffered, buffered Ca2+, and IP3 lifetimes were...
Many signaling, cytoskeletal, and transport proteins have to be localized the plasma membrane (PM) in order carry out their function. We surveyed PM-targeting mechanisms by imaging subcellular localization of 125 fluorescent protein-conjugated Ras, Rab, Arf, Rho proteins. Out 48 that were PM-localized, 37 contained clusters positively charged amino acids. To test whether these polybasic bind negatively phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] lipids, we developed a chemical...
Calcium-calmodulin–dependent protein kinase II (CaMKII) is thought to increase synaptic strength by phosphorylating postsynaptic density (PSD) ion channels and signaling proteins. It shown that N -methyl- D -aspartate (NMDA) receptor stimulation reversibly translocates green fluorescent protein–tagged CaMKII from an F-actin–bound a PSD-bound state. The translocation time was controlled the ratio of expressed β-CaMKII α-CaMKII isoforms. Although F-actin dissociation into cytosol required...
Multifunctional calcium-calmodulin-dependent protein kinase (CaM kinase) transduces transient elevations in intracellular calcium into changes the phosphorylation state and activity of target proteins. By fluorescence emission anisotropy, affinity CaM for dansylated calmodulin was measured found to increase 1000 times after autophosphorylation threonine at position 286 protein. Autophosphorylation markedly slowed release bound calcium-calmodulin; time increased from less than a second...
Stromal interaction molecule 1 (STIM1) has recently been identified by our group and others as an endoplasmic reticulum (ER) Ca(2+) sensor that responds to ER store depletion activates channels in the plasma membrane (PM). The molecular mechanism which STIM1 transduces signals from lumen PM is not yet understood. Here we developed a live-cell FRET approach show forms oligomers within 5 s after depletion. These rapidly dissociated when stores were refilled. We further formed before its...
Phagocytosis requires localized and transient remodeling of actin filaments. Phosphoinositide signaling is believed to play an important role in cytoskeletal organization, but it unclear whether lipids, which can diffuse along the membrane, mediate focal assembly required for phagocytosis. We used imaging fluorescent chimeras pleckstrin homology C1 domains live macrophages monitor distribution phosphatidylinositol-4,5-bisphosphate (4,5-PIP2) diacylglycerol, respectively, during Our results...
To resolve the controversy about messengers regulating KCNQ ion channels during phospholipase C-mediated suppression of current, we designed translocatable enzymes that quickly alter phosphoinositide composition plasma membrane after application a chemical cue. The current falls rapidly to zero when phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2 or PI(4,5)P2] is depleted without changing Ca2+, diacylglycerol, inositol 1,4,5-trisphosphate. Current rises by 30% PI(4,5)P2 overproduced and...
Positive feedback is a ubiquitous signal transduction motif that allows systems to convert graded inputs into decisive, all-or-none outputs. Here we investigate why the positive switches regulate polarization of budding yeast, calcium signaling, Xenopus oocyte maturation, and various other processes use multiple interlinked loops rather than single loops. Mathematical simulations revealed linking fast slow creates "dual-time" switch both rapidly inducible resistant noise in upstream signaling system.
Many cells exhibit periodic transient increases in cytosolic calcium levels rather than a sustained rise when stimulated by hormone or growth factor. We propose here molecular model that accounts for spiking induced constant stimulus. Four elements give to repetitive transients: cooperativity and positive feedback between pair of reciprocally coupled (crosscoupled) messengers, followed deactivation then reactivation. The crosscoupled messengers our are inositol 1,4,5-trisphosphate (InsP3)...
To achieve guide RNA (gRNA) multiplexing and an efficient delivery of tens distinct gRNAs into single cells, we developed a molecular assembly strategy termed chimeric array gRNA oligonucleotides (CARGO). We coupled CARGO with dCas9 (catalytically dead Cas9) imaging to quantitatively measure the movement enhancers promoters that undergo differentiation-associated activity changes in live embryonic stem cells. Whereas all examined functional elements exhibited subdiffusive behavior, their...
Developmental signals such as Wnts are often presented to cells in an oriented manner. To examine the consequences of local Wnt signaling, we immobilized proteins on beads and introduced them embryonic stem culture. At single-cell level, Wnt-bead induced asymmetric distribution Wnt-β-catenin signaling components, plane mitotic division, directed inheritance centrosomes. Before cytokinesis was completed, Wnt-proximal daughter cell expressed high levels nuclear β-catenin pluripotency genes,...
An additional cell cycle checkpoint Cell division is controlled by checkpoints that regulate the temporal order of phases, including G 1 /S, 2 /M, and metaphase/anaphase transitions. Yet there are no known control mechanisms for a fourth fundamental transition—the S/G transition. Saldivar et al. report switchlike mechanism regulates The kinase ATR senses ongoing DNA replication in S phase represses mitotic transcriptional network, ensuring completed before mitosis. Science , this issue p. 806