scholarly journals Quantitative Characterization of Temperature-Independent and Temperature-Dependent Protein–Protein Interactions in Highly Nonideal Solutions

2011 ◽  
Vol 115 (38) ◽  
pp. 11261-11268 ◽  
Author(s):  
Adedayo A. Fodeke ◽  
Allen P. Minton
Keyword(s):  
Protein Interactions ◽  
Protein Protein Interactions ◽  
Temperature Dependent ◽  
Quantitative Characterization ◽  
Dependent Protein

scholarly journals High-Throughput Characterization of Protein-Protein Interactions by Reprogramming Yeast Mating

2017 ◽  
Author(s):  
David Younger ◽  
Stephanie Berger ◽  
David Baker ◽  
Eric Klavins
Keyword(s):  
High Throughput ◽  
Protein Interactions ◽  
Interaction Strength ◽  
Protein Interaction Networks ◽  
Interaction Networks ◽  
Protein Protein Interactions ◽  
Quantitative Characterization ◽  
Mating Efficiency ◽  
Extracellular Environment

AbstractHigh-throughput methods for screening protein-protein interactions enable the rapid characterization of engineered binding proteins and interaction networks. While existing approaches are powerful, none allow quantitative library-on-library characterization of protein interactions in a modifiable extracellular environment. Here, we show that sexual agglutination of S. cerevisiae can be reprogrammed to link interaction strength with mating efficiency using synthetic agglutination (SynAg). Validation of SynAg with 89 previously characterized interactions shows a log-linear relationship between mating efficiency and protein binding strength for interactions with KD’s ranging from below 500 pM to above 300 μM. Using induced chromosomal translocation to pair barcodes representing binding proteins, thousands of distinct interactions can be screened in a single pot. We demonstrate the ability to characterize protein interaction networks in a modifiable environment by introducing a soluble peptide that selectively disrupts a subset of interactions in a representative network by up to 800-fold. SynAg enables the high-throughput, quantitative characterization of protein-protein interaction networks in a fully-defined extracellular environment at a library-on-library scale.Significance StatementDe novo engineering of protein binders often requires experimental screening to select functional variants from a design library. We have achieved high-throughput, quantitative characterization of protein-protein binding interactions without requiring purified recombinant proteins, by linking interaction strength with yeast mating. Using a next-generation sequencing output, we have characterized protein networks consisting of thousands of pairwise interactions in a single tube and have demonstrated the effect of changing the binding environment. This approach addresses an existing bottleneck in protein binder design by enabling the high-throughput and quantitative characterization of binding strength between designed protein libraries and multiple target proteins in a fully defined environment.

scholarly journals Characterization of A-kinase-anchoring disruptors using a solution-based assay

2006 ◽  
Vol 400 (3) ◽  
pp. 493-499 ◽  
Author(s):  
Anne J. Stokka ◽  
Frank Gesellchen ◽  
Cathrine R. Carlson ◽  
John D. Scott ◽  
Friedrich W. Herberg ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Interactions ◽  
Protein Protein Interactions ◽  
Regulatory Subunits ◽  
Anchoring Proteins ◽  
Ic50 Values ◽  
Order Of Magnitude ◽  
Dependent Protein

Subcellular localization of PKA (cAMP-dependent protein kinase or protein kinase A) is determined by protein–protein interactions between its R (regulatory) subunits and AKAPs (A-kinase-anchoring proteins). In the present paper, we report the development of the Amplified Luminescent Proximity Homogeneous Assay (AlphaScreen™) as a means to characterize AKAP-based peptide competitors of PKA anchoring. In this assay, the prototypic anchoring disruptor Ht31 efficiently competed in RIIα isoform binding with RII-specific and dual-specificity AKAPs (IC50 values of 1.4±0.2 nM and 6±1 nM respectively). In contrast, RIα isoform binding to a dual-specific AKAP was less efficiently competed (IC50 of 156±10 nM). Characterization of two RI-selective anchoring disruptors, RIAD (RI-anchoring disruptor) and PV-38 revealed that RIAD (IC50 of 13±1 nM) was 20-fold more potent than PV-38 (IC50 of 304±17 nM) and did not compete in the RIIα–AKAP interaction. We also observed that the kinetics of RII displacement from pre-formed PKA–AKAP complexes and competition of RII–AKAP complex formation by Ht31 differed by an order of magnitude when the component parts were mixed in vitro. No such difference in potency was seen for RIα–AKAP complexes. Thus the AlphaScreen assay may prove to be a valuable tool for detailed characterization of a variety of PKA–AKAP complexes.

scholarly journals Genetic and Molecular Characterization of the Caenorhabditis elegans Gene, mel-26, a Postmeiotic Negative Regulator of MEI-1, a Meiotic-Specific Spindle Component

Genetics ◽  
1998 ◽  
Vol 150 (1) ◽  
pp. 119-128
Author(s):  
M Rhys Dow ◽  
Paul E Mains
Keyword(s):  
Caenorhabditis Elegans ◽  
Protein Interactions ◽  
Negative Regulator ◽  
Meiotic Spindle ◽  
Loss Of Function ◽  
Protein Protein Interactions ◽  
Gain Of Function ◽  
Recessive Mutations ◽  
Female Germline

Abstract We have previously described the gene mei-1, which encodes an essential component of the Caenorhabditis elegans meiotic spindle. When ectopically expressed after the completion of meiosis, mei-1 protein disrupts the function of the mitotic cleavage spindles. In this article, we describe the cloning and the further genetic characterization of mel-26, a postmeiotic negative regulator of mei-1. mel-26 was originally identified by a gain-of-function mutation. We have reverted this mutation to a loss-of-function allele, which has recessive phenotypes identical to the dominant defects of its gain-of-function parent. Both the dominant and recessive mutations of mel-26 result in mei-1 protein ectopically localized in mitotic spindles and centrosomes, leading to small and misoriented cleavage spindles. The loss-of-function mutation was used to clone mel-26 by transformation rescue. As suggested by genetic results indicating that mel-26 is required only maternally, mel-26 mRNA was expressed predominantly in the female germline. The gene encodes a protein that includes the BTB motif, which is thought to play a role in protein-protein interactions.

Proteomic Characterization of Protein-Protein Interactions

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Veenstra TD ◽  
Keyword(s):  
Protein Interactions ◽  
Disease Diagnosis ◽  
Cell System ◽  
Protein Protein Interactions ◽  
Novel Technologies ◽  
Cell Functions ◽  
Single Protein ◽  
A Cell ◽  
Molecular Components

Identifying all the molecular components within a living cell is the first step into understanding how it functions. To further understand how a cell functions requires identifying the interactions that occur between these components. This fact is especially relevant for proteins. No protein within a human cell functions on its own without interacting with another biomolecule - usually another protein. While Protein-Protein Interactions (PPI) have historically been determined by examining a single protein per study, novel technologies developed over the past couple of decades are enabling high-throughput methods that aim to describe entire protein networks within cells. In this review, some of the technologies that have led to these developments are described along with applications of these techniques. Ultimately the goal of these technologies is to map out the entire circuitry of PPI within human cells to be able to predict the global consequences of perturbations to the cell system. This predictive capability will have major impacts on the future of both disease diagnosis and treatment.

scholarly journals Characterization of major chromatin assembly proteins in tetrahymena thermophile using proeomic and molecular evolutionary analyses

2021 ◽  
Author(s):  
Syed N Shah
Keyword(s):  
Protein Interactions ◽  
Protein Complexes ◽  
Affinity Purification ◽  
Regulation Of Gene Expression ◽  
Chromatin Assembly ◽  
Histone Chaperones ◽  
Protein Protein Interactions ◽  
Selective Forces ◽  
Assembly Proteins

Histones H3/H4 are deposited onto DNA in a replication-dependent or independent fashion by the CAF1 and HIRA protein complexes. Despite the identification of these protein complexes, mechanistic details remain unclear. Recently, we showed that in T. thermophila histone chaperones Nrp1, Asf1 and the Impβ6 importin function together to transport newly synthesized H3/H4 from the cytoplasm to the nucleus. To characterize chromatin assembly proteins in T.thermophila, I used affinity purification combined with mass spectrometry to identify protein-protein interactions of Nrp1, Cac2 subunit of CAF1, HIRA and histone modifying Hat1-complex in T. thermophila. I found that the three-subunit T.thermophila CAF1 complex interacts with Casein Kinase 2 (CKII), possibly accounting for previously reported human CAF1phosphorylation. I also found that Hat2 subunit of HAT1 complex is also shared by CAF1 complex as its Cac3 subunit. This suggests that Hat2/Cac3 might exist in two separate pools of protein complexes. Remarkably, proteomic analysis of Hat2/Cac3 in turn revealed that it forms several complexes with other proteins including SIN3, RXT3, LIN9 and TESMIN, all of which have known roles in the regulation of gene expression. Finally, I asked how selective forces might have impacted on the function of proteins involved in H3/H4 transport. Focusing on NASP which possesses several TPR motifs, I showed that its protein-protein interactions are conserved in T. thermophila. Using molecular evolutionary methods I show that different TPRs in NASP evolve at different rates possibly accounting for the functional diversity observed among different family members.

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