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Articles 1 - 6 of 6
Full-Text Articles in Cell and Developmental Biology
Modeling And Analyzing An Optogenetic System For Photoactivatable Protein Dissociation, Anvin Thomas, James Schaff
Modeling And Analyzing An Optogenetic System For Photoactivatable Protein Dissociation, Anvin Thomas, James Schaff
Honors Scholar Theses
Computational modeling of cell-cell interactions can grant clues and can answer questions about an experiment, especially for observations about binding interactions and kinetics. This approach was used to investigate an interaction between a light-oxygen-voltage (LOV) domain and an engineered protein called Zdark (Zdk). The LOV domain is membrane-bound while Zdk is cytosolic. The LOV domain and Zdk bind strongly in dark (Kd 26.2 nM), and weakly upon exposure to blue light (Kd > 4 μM). Total internal reflection fluorescence (TIRF) images are acquired of Zdk, the fluorescent species bound to a mCherry tag, and the loss of fluorescence is …
Endonucleolytic Cleavage In The Expansion Segment 7 Of 25s Rrna Is An Early Marker Of Low-Level Oxidative Stress In Yeast, Daniel Shedlovskiy, Jessica A Zinskie, Ethan Gardner, Dimitri G Pestov, Natalia Shcherbik
Endonucleolytic Cleavage In The Expansion Segment 7 Of 25s Rrna Is An Early Marker Of Low-Level Oxidative Stress In Yeast, Daniel Shedlovskiy, Jessica A Zinskie, Ethan Gardner, Dimitri G Pestov, Natalia Shcherbik
Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship
The ability to detect and respond to oxidative stress is crucial to the survival of living organisms. In cells, sensing of increased levels of reactive oxygen species (ROS) activates many defensive mechanisms that limit or repair damage to cell components. The ROS-signaling responses necessary for cell survival under oxidative stress conditions remain incompletely understood, especially for the translational machinery. Here, we found that drug treatments or a genetic deficiency in the thioredoxin system that increase levels of endogenous hydrogen peroxide in the yeast Saccharomyces cerevisiae promote site-specific endonucleolytic cleavage in 25S ribosomal RNA (rRNA) adjacent to the c loop of …
Release Of Camp Gating By The Alpha6beta4 Integrin Stimulates Lamellae Formation And The Chemotactic Migration Of Invasive Carcinoma Cells, Kathleen L. O'Connor, Leslie M. Shaw, Arthur M. Mercurio
Release Of Camp Gating By The Alpha6beta4 Integrin Stimulates Lamellae Formation And The Chemotactic Migration Of Invasive Carcinoma Cells, Kathleen L. O'Connor, Leslie M. Shaw, Arthur M. Mercurio
Arthur M. Mercurio
The alpha6beta4 integrin promotes carcinoma in-vasion by its activation of a phosphoinositide 3-OH (PI3-K) signaling pathway (Shaw, L.M., I. Rabinovitz, H.H.-F. Wang, A. Toker, and A.M. Mercurio. Cell. 91: 949-960). We demonstrate here using MDA-MB-435 breast carcinoma cells that alpha6beta4 stimulates chemotactic migration, a key component of invasion, but that it has no influence on haptotaxis. Stimulation of chemotaxis by alpha6beta4 expression was observed in response to either lysophosphatidic acid (LPA) or fibroblast conditioned medium. Moreover, the LPA-dependent formation of lamellae in these cells is dependent upon alpha6beta4 expression. Both lamellae formation and chemotactic migration are inhibited or "gated" by …
Dictyostelium Discoideum Plasma Membranes Contain An Actin-Nucleating Activity That Requires Ponticulin, An Integral Membrane Glycoprotein, A. Shariff, Elizabeth J. Luna
Dictyostelium Discoideum Plasma Membranes Contain An Actin-Nucleating Activity That Requires Ponticulin, An Integral Membrane Glycoprotein, A. Shariff, Elizabeth J. Luna
Elizabeth J. Luna
In previous equilibrium binding studies, Dictyostelium discoideum plasma membranes have been shown to bind actin and to recruit actin into filaments at the membrane surface. However, little is known about the kinetic pathway(s) through which actin assembles at these, or other, membranes. We have used actin fluorescently labeled with N-(1-pyrenyl)iodoacetamide to examine the kinetics of actin assembly in the presence of D. discoideum plasma membranes. We find that these membranes increase the rate of actin polymerization. The rate of membrane-mediated actin polymerization is linearly dependent on membrane protein concentrations up to 20 micrograms/ml. Nucleation (the association of activated actin monomers …
Binding And Assembly Of Actin Filaments By Plasma Membranes From Dictyostelium Discoideum, M. A. Schwartz, Elizabeth J. Luna
Binding And Assembly Of Actin Filaments By Plasma Membranes From Dictyostelium Discoideum, M. A. Schwartz, Elizabeth J. Luna
Elizabeth J. Luna
The binding of native, 125I-Bolton-Hunter-labeled actin to purified Dictyostelium discoideum plasma membranes was measured using a sedimentation assay. Binding was saturable only in the presence of the actin capping protein, gelsolin. In the presence of gelsolin, the amount of actin bound at saturation to three different membrane preparations was 80, 120, and 200 micrograms/mg of membrane protein. The respective concentrations of actin at half-saturation were 8, 12, and 18 micrograms/ml. The binding curves were sigmoidal, indicating positive cooperativity at low actin concentrations. This cooperativity appeared to be due to actin-actin associations during polymerization, since phalloidin converted the curve to a …
Detergent Extraction Of A Presumptive Gating Component From The Voltage-Dependent Sodium Channel, W J. Culp, D T. Mckenzie
Detergent Extraction Of A Presumptive Gating Component From The Voltage-Dependent Sodium Channel, W J. Culp, D T. Mckenzie
Dartmouth Scholarship
A physiologically characterized radiolabeled neurotoxin complex obtained from venom of the scorpion Leiurus quinquestriatus has been used to identify detergent-solubilized presumptive sodium channel components in sucrose gradients. This toxin-binding component is found in extracts prepared from three sources of excitable membrane but appears to be absent from similar extracts prepared from nonexcitable membrane or from Torpedo californica membrane. Procedures that destroy the physiological activity of the Leiurus neurotoxin lead to a corresponding loss of toxin binding to the putative sodium channel component. The major component recognized by the Leiurus toxin sediments at 6.5 S. Scatchard analysis of quantitative binding experiments …