Split-EGFP Screens for the Detection and Localisation of Protein–Protein Interactions in Living Yeast Cells

Author(s):  
Emma Barnard ◽  
David J. Timson
1991 ◽  
Vol 11 (10) ◽  
pp. 5101-5112
Author(s):  
J S Flick ◽  
M Johnston

Growth of the yeast Saccharomyces cerevisiae on glucose leads to repression of transcription of many genes required for alternative carbohydrate metabolism. The GRR1 gene appears to be of central importance to the glucose repression mechanism, because mutations in GRR1 result in a pleiotropic loss of glucose repression (R. Bailey and A. Woodword, Mol. Gen. Genet. 193:507-512, 1984). We have isolated the GRR1 gene and determined that null mutants are viable and display a number of growth defects in addition to the loss of glucose repression. Surprisingly, grr1 mutations convert SUC2, normally a glucose-repressed gene, into a glucose-induced gene. GRR1 encodes a protein of 1,151 amino acids that is expressed constitutively at low levels in yeast cells. GRR1 protein contains 12 tandem repeats of a sequence similar to leucine-rich motifs found in other proteins that may mediate protein-protein interactions. Indeed, cell fractionation studies are consistent with this view, suggesting that GRR1 protein is tightly associated with a particulate protein fraction in yeast extracts. The combined genetic and molecular data are consistent with the idea that GRR1 protein is a primary response element in the glucose repression pathway and is required for the generation or interpretation of the signal that induces glucose repression.


1991 ◽  
Vol 11 (10) ◽  
pp. 5101-5112 ◽  
Author(s):  
J S Flick ◽  
M Johnston

Growth of the yeast Saccharomyces cerevisiae on glucose leads to repression of transcription of many genes required for alternative carbohydrate metabolism. The GRR1 gene appears to be of central importance to the glucose repression mechanism, because mutations in GRR1 result in a pleiotropic loss of glucose repression (R. Bailey and A. Woodword, Mol. Gen. Genet. 193:507-512, 1984). We have isolated the GRR1 gene and determined that null mutants are viable and display a number of growth defects in addition to the loss of glucose repression. Surprisingly, grr1 mutations convert SUC2, normally a glucose-repressed gene, into a glucose-induced gene. GRR1 encodes a protein of 1,151 amino acids that is expressed constitutively at low levels in yeast cells. GRR1 protein contains 12 tandem repeats of a sequence similar to leucine-rich motifs found in other proteins that may mediate protein-protein interactions. Indeed, cell fractionation studies are consistent with this view, suggesting that GRR1 protein is tightly associated with a particulate protein fraction in yeast extracts. The combined genetic and molecular data are consistent with the idea that GRR1 protein is a primary response element in the glucose repression pathway and is required for the generation or interpretation of the signal that induces glucose repression.


Author(s):  
Karla V. Teymennet-Ramírez ◽  
Fernando Martínez-Morales ◽  
María R. Trejo-Hernández

Yeast surface display (YSD) is a “whole-cell” platform used for the heterologous expression of proteins immobilized on the yeast’s cell surface. YSD combines the advantages eukaryotic systems offer such as post-translational modifications, correct folding and glycosylation of proteins, with ease of cell culturing and genetic manipulation, and allows of protein immobilization and recovery. Additionally, proteins displayed on the surface of yeast cells may show enhanced stability against changes in temperature, pH, organic solvents, and proteases. This platform has been used to study protein-protein interactions, antibody design and protein engineering. Other applications for YSD include library screening, whole-proteome studies, bioremediation, vaccine and antibiotics development, production of biosensors, ethanol production and biocatalysis. YSD is a promising technology that is not yet optimized for biotechnological applications. This mini review is focused on recent strategies to improve the efficiency and selection of displayed proteins. YSD is presented as a cutting-edge technology for the vectorial expression of proteins and peptides. Finally, recent biotechnological applications are summarized. The different approaches described herein could allow for a better strategy cascade for increasing protein/peptide interaction and production.


2017 ◽  
Author(s):  
Osman N. Yogurtcu ◽  
Margaret E. Johnson

ABSTRACTCell division, endocytosis, and viral budding would not function without the localization and assembly of protein complexes on membranes. What is poorly appreciated, however, is that by localizing to membranes, proteins search in a reduced space that effectively drives up concentration. Here we derive an accurate and practical analytical theory to quantify the significance of this dimensionality reduction in regulating protein assembly on membranes. We define a simple metric, an effective equilibrium constant, that allows for quantitative comparison of protein-protein interactions with and without membrane present. To test the importance of membrane localization for driving protein assembly, we collected the protein-protein and protein-lipid affinities, protein and lipid concentrations, and volume-to-surface-area ratios for 46 interactions between 37 membrane-targeting proteins in human and yeast cells. We find that many of the protein-protein interactions between pairs of proteins involved in clathrin-mediated endocytosis in human and yeast cells can experience enormous increases in effective protein-protein affinity (10-1000 fold) due to membrane localization. Localization of binding partners thus triggers robust protein complexation, suggesting that it can play an important role in controlling the timing of endocytic protein coat formation. Our analysis shows that several other proteins involved in membrane remodeling at various organelles have similar potential to exploit localization. The theory highlights the master role of phosphoinositide lipid concentration, the volume-to-surface-area ratio, and the ratio of 3D to 2D equilibrium constants in triggering (or preventing) constitutive assembly on membranes. Our simple model provides a novel quantitative framework for interpreting or designing in vitro experiments of protein complexation influenced by membrane binding.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Chitra Mohan ◽  
Lisa M Kim ◽  
Nicole Hollar ◽  
Tailai Li ◽  
Eric Paulissen ◽  
...  

VivosX is an in vivo disulfide crosslinking approach that utilizes a pair of strategically positioned cysteines on two proteins to probe physical interactions within cells. Histone H2A.Z, which often replaces one or both copies of H2A in nucleosomes downstream of promoters, was used to validate VivosX. Disulfide crosslinks between cysteine-modified H2A.Z and/or H2A histones within nucleosomes were induced using a membrane-permeable oxidant. VivosX detected different combinations of H2A.Z and H2A within nucleosomes in yeast cells. This assay correctly reported the change in global H2A.Z occupancy previously observed when the deposition and eviction pathways of H2A.Z were perturbed. Homotypic H2A.Z/H2A.Z (ZZ) nucleosomes accumulated when assembly of the transcription preinitiation complex was blocked, revealing that the transcription machinery preferentially disassembles ZZ nucleosomes. VivosX works in human cells and distinguishes ZZ nucleosomes with one or two ubiquitin moieties, demonstrating that it can be used to detect protein-protein interactions inside cells from different species.


2011 ◽  
Vol 49 (08) ◽  
Author(s):  
LC König ◽  
M Meinhard ◽  
C Sandig ◽  
MH Bender ◽  
A Lovas ◽  
...  

1974 ◽  
Vol 31 (03) ◽  
pp. 403-414 ◽  
Author(s):  
Terence Cartwright

SummaryA method is described for the extraction with buffers of near physiological pH of a plasminogen activator from porcine salivary glands. Substantial purification of the activator was achieved although this was to some extent complicated by concomitant extraction of nucleic acid from the glands. Preliminary characterization experiments using specific inhibitors suggested that the activator functioned by a similar mechanism to that proposed for urokinase, but with some important kinetic differences in two-stage assay systems. The lack of reactivity of the pig gland enzyme in these systems might be related to the tendency to protein-protein interactions observed with this material.


2020 ◽  
Author(s):  
Salvador Guardiola ◽  
Monica Varese ◽  
Xavier Roig ◽  
Jesús Garcia ◽  
Ernest Giralt

<p>NOTE: This preprint has been retracted by consensus from all authors. See the retraction notice in place above; the original text can be found under "Version 1", accessible from the version selector above.</p><p><br></p><p>------------------------------------------------------------------------</p><p><br></p><p>Peptides, together with antibodies, are among the most potent biochemical tools to modulate challenging protein-protein interactions. However, current structure-based methods are largely limited to natural peptides and are not suitable for designing target-specific binders with improved pharmaceutical properties, such as macrocyclic peptides. Here we report a general framework that leverages the computational power of Rosetta for large-scale backbone sampling and energy scoring, followed by side-chain composition, to design heterochiral cyclic peptides that bind to a protein surface of interest. To showcase the applicability of our approach, we identified two peptides (PD-<i>i</i>3 and PD-<i>i</i>6) that target PD-1, a key immune checkpoint, and work as protein ligand decoys. A comprehensive biophysical evaluation confirmed their binding mechanism to PD-1 and their inhibitory effect on the PD-1/PD-L1 interaction. Finally, elucidation of their solution structures by NMR served as validation of our <i>de novo </i>design approach. We anticipate that our results will provide a general framework for designing target-specific drug-like peptides.<i></i></p>


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