scholarly journals Structure of Fungal α Mating Pheromone in Membrane Mimetics Suggests a Possible Role for Regulation at the Water-Membrane Interface

2020 ◽  
Vol 11 ◽  
Author(s):  
Angélica Partida-Hanon ◽  
Moisés Maestro-López ◽  
Stefania Vitale ◽  
David Turrà ◽  
Antonio Di Pietro ◽  
...  
Keyword(s):  
Membrane Interface ◽  
Mating Pheromone

Two-Dimensional Crystallization of Tetanus Toxin

1985 ◽  
Vol 43 ◽  
pp. 528-529
Author(s):  
Jeffry A. Reidler ◽  
John P. Robinson
Keyword(s):  
Electron Microscopy ◽  
Tetanus Toxin ◽  
Structural Information ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Membrane Interface ◽  
3D Reconstructions ◽  
Cellular Receptors ◽  
Computer Reconstruction ◽  
2D Crystals

We have prepared two-dimensional (2D) crystals of tetanus toxin using procedures developed by Uzgiris and Kornberg for the directed production of 2D crystals of monoclonal antibodies at an antigen-phospholipid monolayer interface. The tetanus toxin crystals were formed using a small mole fraction of the natural receptor, GT1, incorporated into phosphatidyl choline monolayers. The crystals formed at low concentration overnight. Two dimensional crystals of this type are particularly useful for structure determination using electron microscopy and computer image refinement. Three dimensional (3D) structural information can be derived from these crystals by computer reconstruction of photographs of toxin crystals taken at different tilt angles. Such 3D reconstructions may help elucidate the mechanism of entry of the enzymatic subunit of toxins into cells, particularly since these crystals form directly on a membrane interface at similar concentrations of ganglioside GT1 to the natural cellular receptors.

Phase Transitions in Phospholipid Monolayers Studied by Atomic Force Microscopy and Langmuir-Blodgett Technique

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Maria Tomoaia-Cotisel ◽  
Aurora Mocanu
Keyword(s):  
Atomic Force Microscopy ◽  
Lipid Membrane ◽  
Phase Behaviour ◽  
Membrane Interface ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
Atomic Force ◽  
Phospholipid Monolayers ◽  
Air Water Interface ◽  
Condensed Liquid

The phase behaviour and surface structure of dipalmitoyl phosphatidyl choline (DPPC) monolayers at the air/water interface, in the absence and the presence of procaine, have been investigated by Langmuir-Blodgett (LB) technique and atomic force microscopy. The LB films were transferred on mica, at a controlled surface pressure, characteristic for the expanded liquid to condensed liquid phase transition of pure DPPC monolayers. The results indicate that procaine penetrates into and specifically interacts with phospholipid monolayers stabilizing the lipid membrane interface.

scholarly journals Mot3, a Zn Finger Transcription Factor That Modulates Gene Expression and Attenuates Mating Pheromone Signaling in Saccharomyces cerevisiae

Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 879-892 ◽  
Author(s):  
Anatoly V Grishin ◽  
Michael Rothenberg ◽  
Maureen A Downs ◽  
Kendall J Blumer
Keyword(s):  
Gene Expression ◽  
Saccharomyces Cerevisiae ◽  
Signaling Pathway ◽  
G Protein ◽  
Binding Sites ◽  
Dependent Manner ◽  
Pheromone Response ◽  
Mating Pheromone ◽  
Pheromone Signaling ◽  
Yeast Genes

Abstract In the yeast Saccharomyces cerevisiae, mating pheromone response is initiated by activation of a G protein- and mitogen-activated protein (MAP) kinase-dependent signaling pathway and attenuated by several mechanisms that promote adaptation or desensitization. To identify genes whose products negatively regulate pheromone signaling, we screened for mutations that suppress the hyperadaptive phenotype of wild-type cells overexpressing signaling-defective G protein β subunits. This identified recessive mutations in MOT3, which encodes a nuclear protein with two Cys2-His2 Zn fingers. MOT3 was found to be a dosage-dependent inhibitor of pheromone response and pheromone-induced gene expression and to require an intact signaling pathway to exert its effects. Several results suggested that Mot3 attenuates expression of pheromone-responsive genes by mechanisms distinct from those used by the negative transcriptional regulators Cdc36, Cdc39, and Mot2. First, a Mot3-lexA fusion functions as a transcriptional activator. Second, Mot3 is a dose-dependent activator of several genes unrelated to pheromone response, including CYC1, SUC2, and LEU2. Third, insertion of consensus Mot3 binding sites (C/A/T)AGG(T/C)A activates a promoter in a MOT3-dependent manner. These findings, and the fact that consensus binding sites are found in the 5′ flanking regions of many yeast genes, suggest that Mot3 is a globally acting transcriptional regulator. We hypothesize that Mot3 regulates expression of factors that attenuate signaling by the pheromone response pathway.

scholarly journals THE SELECTION OF S. CEREVISIAE MUTANTS DEFECTIVE IN THE START EVENT OF CELL DIVISION

Genetics ◽  
1980 ◽  
Vol 95 (3) ◽  
pp. 561-577 ◽  
Author(s):  
Steven I Reed
Keyword(s):  
Cell Division ◽  
Genetic Analysis ◽  
Linkage Map ◽  
Nuclear Genes ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Mating Pheromone ◽  
Preliminary Characterization ◽  
Complementation Groups ◽  
Selection Of

ABSTRACT Thirty-three temperature-sensitive mutations defective in the start event of the cell division cycle of Saccharomyces cereuisiae were isolated and subjected to preliminary characterization. Complementation studies assigned these mutations to four complementation groups, one of which, cdc28, has been described previously. Genetic analysis revealed that these complementation groups define single nuclear genes, unlinked to one another. One of the three newly identified genes, cdc37, has been located in the yeast linkage map on chromosome IV, two meiotic map units distal to hom2.—Each mutation produces stage-specific arrest of cell division at start, the same point where mating pheromone interrupts division. After synchronization at start by incubation at the restrictive temperature, the mutants retain the capacity to enlarge and to conjugate.

scholarly journals A Ste6p/P-glycoprotein homologue from the asexual yeast Candida albicans transports the a-factor mating pheromone in Saccharomyces cerevisiae

1998 ◽  
Vol 27 (3) ◽  
pp. 587-598 ◽  
Author(s):  
Martine Raymond ◽  
Daniel Dignard ◽  
Anne-Marie Alarco ◽  
Norman Mainville ◽  
Beatrice B. Magee ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Mating Pheromone ◽  
P Glycoprotein

Transient Water Transport in Nafion Membranes Under Activity Gradients

2010 ◽  
Author(s):  
T. Romero ◽  
W. Me´rida
Keyword(s):  
Water Content ◽  
Water Transport ◽  
Water Activity ◽  
Thickness Variation ◽  
Membrane Thickness ◽  
Membrane Interface ◽  
Rational Representation ◽  
Transport Measurements ◽  
Nafion Membranes ◽  
The Time Domain

Transient water transport experiments on Nafion of different thicknesses were carried out in the temperature range of 30 to 70 °C. These experiments report on water transport measurements under activity gradients in the time domain for liquid and vapour equilibrated Nafion membranes. Using a permeability test rig with a gated valve, the water crossover was measured as a function of time. The typical response is shown as a time dependent flux, and it shows the dynamic transport from an initially dry condition up to the final steady state. Contrarily to previous reports from dynamic water transport measurements, where the activity gradient across the membrane is absent; in this work, the membrane was subjected to an activity gradient acting as the driving force to transport water from an environment with higher water activity to an environment with lower water activity through the membrane’s structure. Measurements explored temperature and membrane thickness variation effect on the transient response. Results showed dependency on temperature and a slower water transport rate across the vapour-membrane interface than for the liquid-membrane interface. These measurements showed the transport dependency on water content at the beginning of the experiment when the membrane was in a close-to-dry condition suggesting a transport phenomenon transition due to a reached critical water content value. The new protocol for transient measurements proposed here will allow the characterization of water transport dependency on membrane water content with a more rational representation of the membrane-environment interface.

scholarly journals Membrane Interface Composition Drives the Structure and the Tilt of the Single Transmembrane Helix Protein PMP1: MD Studies

2011 ◽  
Vol 100 (7) ◽  
pp. 1660-1667 ◽  
Author(s):  
Veronica Beswick ◽  
Adriana Isvoran ◽  
Pierre Nédellec ◽  
Alain Sanson ◽  
Nadège Jamin
Keyword(s):  
Transmembrane Helix ◽  
Membrane Interface ◽  
Interface Composition

Interaction of a peptide nanotube with a water–membrane interface

2006 ◽  
Vol 3 (1) ◽  
pp. S20-S25 ◽  
Author(s):  
Christophe Chipot ◽  
Mounir Tarek
Keyword(s):  
Membrane Interface ◽  
Peptide Nanotube
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