scholarly journals The amino- and carboxyl-terminal tails of (beta)-catenin reduce its affinity for desmoglein 2

2000 ◽  
Vol 113 (10) ◽  
pp. 1737-1745 ◽  
Author(s):  
J.K. Wahl ◽  
J.E. Nieset ◽  
P.A. Sacco-Bubulya ◽  
T.M. Sadler ◽  
K.R. Johnson ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Interactions ◽  
Adherens Junction ◽  
Beta Catenin ◽  
Protein Protein Interactions ◽  
Desmosomal Cadherins ◽  
Classical Cadherins ◽  
Show Evidence ◽  
Carboxyl Terminal ◽  
Armadillo Repeats

beta-catenin and plakoglobin are members of the armadillo family of proteins and were first identified as components of intercellular adhering junctions. In the adherens junction beta-catenin and plakoglobin serve to link classical cadherins to the actin-based cytoskeleton. In the desmosome plakoglobin links the desmosomal cadherins, the desmogleins and the desmocollins, to the intermediate filament cytoskeleton. beta-catenin is not a component of the desmosome. Previously we have shown that the central armadillo repeat region of plakoglobin is the site for desmosomal cadherin binding. We hypothesized that the unique amino- and/or carboxyl-terminal ends of beta-catenin may regulate its exclusion from the desmosomal plaque. To test this hypothesis we used chimeras between beta-catenin and plakoglobin to identify domain(s) that modulate association with desmoglein 2. Chimeric constructs, each capable of associating with classical cadherins, were assayed for association with the desmosomal cadherin desmoglein 2. Addition of either the N- or C-terminal tail of beta-catenin to the armadillo repeats of plakoglobin did not interfere with desmoglein 2 association. However, when both beta-catenin amino terminus and carboxyl terminus were added to the plakoglobin armadillo repeats, association with desmoglein 2 was diminished. Removal of the first 26 amino acids from this construct restored association. We show evidence for direct protein-protein interactions between the amino- and carboxyl-terminal tails of beta-catenin and propose that a sequence in the first 26 amino acids of beta-catenin along with its carboxyl-terminal tail decrease its affinity for desmoglein and prevent its inclusion in the desmosome.

Molecular interactions between desmosomal cadherins

2002 ◽  
Vol 362 (2) ◽  
pp. 317-327 ◽  
Author(s):  
Shabih-e-Hassnain SYED ◽  
Brian TRINNAMAN ◽  
Stephen MARTIN ◽  
Sarah MAJOR ◽  
Jon HUTCHINSON ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Analytical Ultracentrifugation ◽  
Expression System ◽  
Quantitative Information ◽  
Cell Junctions ◽  
Protein Protein Interactions ◽  
Desmosomal Cadherins ◽  
Classical Cadherins ◽  
Escherichia Coli Expression

Desmocollins (Dscs) and desmogleins (Dsgs) are cell-adhesion molecules involved in the formation of desmosome cell—cell junctions and share structural similarities to classical cadherins such as E-cadherin. In order to identify and provide quantitative information on the types of protein—protein interactions displayed by the type 2 isoforms and investigate the role of Ca2+ in this process, we have developed an Escherichia coli expression system to generate recombinant proteins containing the first two extracellular domains, namely Dsg2(1-2) and Dsc2(1-2). Analytical ultracentrifugation, chemical cross-linking, CD, fluorescence and BIAcore have been used to provide the first direct evidence of Ca2+ binding to desmosomal cadherins. These studies suggest that Dsc2(1-2) not only exhibits homophilic interactions in solution, but can also form heterophilic interactions with Dsg2(1-2). The latter, on the other hand, shows much weaker homophilic association. Our results further demonstrate that heterophilic interactions are Ca2+-dependent, whereas the Ca2+-dependence of homophilic association is less clear. Our data indicate that the functional properties of Dsc2(1-2) are more similar to those of classical cadherins, consistent with the observation that Dsc shares a higher level of sequence homology with classical cadherins than does Dsg. In addition to corroborating the conclusions of previously reported transfection studies which suggest the formation of lateral heterodimers and homodimers, our results also provide direct quantitative information on the strength of these interactions which are essential for understanding the adhesion mechanism.

Exploring Proteomic Drug Targets, Therapeutic Strategies and Protein - Protein Interactions in Cancer: Mechanistic View

2019 ◽  
Vol 19 (6) ◽  
pp. 430-448 ◽  
Author(s):  
Khalid Bashir Dar ◽  
Aashiq Hussain Bhat ◽  
Shajrul Amin ◽  
Syed Anjum ◽  
Bilal Ahmad Reshi ◽  
...  
Keyword(s):  
Protein Interactions ◽  
High Throughput Screening ◽  
Critical Role ◽  
Cancer Therapeutics ◽  
Adaptor Proteins ◽  
Therapeutic Strategies ◽  
Small Gtpases ◽  
Beta Catenin ◽  
Protein Protein Interactions ◽  
Apoptosis Protein

Protein-Protein Interactions (PPIs) drive major signalling cascades and play critical role in cell proliferation, apoptosis, angiogenesis and trafficking. Deregulated PPIs are implicated in multiple malignancies and represent the critical targets for treating cancer. Herein, we discuss the key protein-protein interacting domains implicated in cancer notably PDZ, SH2, SH3, LIM, PTB, SAM and PH. These domains are present in numerous enzymes/kinases, growth factors, transcription factors, adaptor proteins, receptors and scaffolding proteins and thus represent essential sites for targeting cancer. This review explores the candidature of various proteins involved in cellular trafficking (small GTPases, molecular motors, matrix-degrading enzymes, integrin), transcription (p53, cMyc), signalling (membrane receptor proteins), angiogenesis (VEGFs) and apoptosis (BCL-2family), which could possibly serve as targets for developing effective anti-cancer regimen. Interactions between Ras/Raf; X-linked inhibitor of apoptosis protein (XIAP)/second mitochondria-derived activator of caspases (Smac/DIABLO); Frizzled (FRZ)/Dishevelled (DVL) protein; beta-catenin/T Cell Factor (TCF) have also been studied as prospective anticancer targets. Efficacy of diverse molecules/ drugs targeting such PPIs although evaluated in various animal models/cell lines, there is an essential need for human-based clinical trials. Therapeutic strategies like the use of biologicals, high throughput screening (HTS) and fragment-based technology could play an imperative role in designing cancer therapeutics. Moreover, bioinformatic/computational strategies based on genome sequence, protein sequence/structure and domain data could serve as competent tools for predicting PPIs. Exploring hot spots in proteomic networks represents another approach for developing targetspecific therapeutics. Overall, this review lays emphasis on a productive amalgamation of proteomics, genomics, biochemistry, and molecular dynamics for successful treatment of cancer.

scholarly journals Interactions between Integrase and Excisionase in the Phage Lambda Excisive Nucleoprotein Complex

2002 ◽  
Vol 184 (18) ◽  
pp. 5200-5203 ◽  
Author(s):  
Eun Hee Cho ◽  
Richard I. Gumport ◽  
Jeffrey F. Gardner
Keyword(s):  
Protein Interactions ◽  
Protein Protein Interactions ◽  
Mobility Shift ◽  
Host Chromosome ◽  
Amino Terminal ◽  
Nucleoprotein Complex ◽  
Carboxyl Terminal ◽  
Α Helix ◽  
Gel Mobility Shift ◽  
Amino Terminal Domain

ABSTRACT Bacteriophage lambda site-specific recombination comprises two overall reactions, integration into and excision from the host chromosome. Lambda integrase (Int) carries out both reactions. During excision, excisionase (Xis) helps Int to bind DNA and introduces a bend in the DNA that facilitates formation of the proper excisive nucleoprotein complex. The carboxyl-terminal α-helix of Xis is thought to interact with Int through direct protein-protein interactions. In this study, we used gel mobility shift assays to show that the amino-terminal domain of Int maintained cooperative interactions with Xis. This finding indicates that the amino-terminal arm-type DNA binding domain of Int interacts with Xis.

scholarly journals β-Catenin is a pH sensor with decreased stability at higher intracellular pH

2018 ◽  
Vol 217 (11) ◽  
pp. 3965-3976 ◽  
Author(s):  
Katharine A. White ◽  
Bree K. Grillo-Hill ◽  
Mario Esquivel ◽  
Jobelle Peralta ◽  
Vivian N. Bui ◽  
...  
Keyword(s):  
Intracellular Ph ◽  
Protein Interactions ◽  
Mammalian Cells ◽  
Ph Sensor ◽  
Adherens Junction ◽  
Protein Protein Interactions ◽  
Adherens Junction Protein ◽  
Junction Protein ◽  
Evolutionarily Conserved ◽  
Ph Dependent

β-Catenin functions as an adherens junction protein for cell–cell adhesion and as a signaling protein. β-catenin function is dependent on its stability, which is regulated by protein–protein interactions that stabilize β-catenin or target it for proteasome-mediated degradation. In this study, we show that β-catenin stability is regulated by intracellular pH (pHi) dynamics, with decreased stability at higher pHi in both mammalian cells and Drosophila melanogaster. β-Catenin degradation requires phosphorylation of N-terminal residues for recognition by the E3 ligase β-TrCP. While β-catenin phosphorylation was pH independent, higher pHi induced increased β-TrCP binding and decreased β-catenin stability. An evolutionarily conserved histidine in β-catenin (found in the β-TrCP DSGIHS destruction motif) is required for pH-dependent binding to β-TrCP. Expressing a cancer-associated H36R–β-catenin mutant in the Drosophila eye was sufficient to induce Wnt signaling and produced pronounced tumors not seen with other oncogenic β-catenin alleles. We identify pHi dynamics as a previously unrecognized regulator of β-catenin stability, functioning in coincidence with phosphorylation.

scholarly journals PF16 encodes a protein with armadillo repeats and localizes to a single microtubule of the central apparatus in Chlamydomonas flagella.

1996 ◽  
Vol 132 (3) ◽  
pp. 359-370 ◽  
Author(s):  
E F Smith ◽  
P A Lefebvre
Keyword(s):  
Protein Interactions ◽  
Insertional Mutagenesis ◽  
Flagellar Motility ◽  
Wild Type ◽  
Protein Protein Interactions ◽  
Cellular Functions ◽  
Central Pair ◽  
Central Apparatus ◽  
Immunofluorescence Labeling ◽  
Armadillo Repeats

Several studies have indicated that the central pair of microtubules and their associated structures play a significant role in regulating flagellar motility. To begin a molecular analysis of these components we have generated central apparatus-defective mutants in Chlamydomonas reinhardtii using insertional mutagenesis. One paralyzed mutant recovered in our screen, D2, is an allele of a previously identified mutant, pf16. Mutant cells have paralyzed flagella, and the C1 microtubule of the central apparatus is missing in isolated axonemes. We have cloned the wild-type PF16 gene and confirmed its identity by rescuing pf16 mutants upon transformation. The rescued pf16 cells were wild-type in motility and in axonemal ultrastructure. A full-length cDNA clone for PF16 was obtained and sequenced. Database searches using the predicted 566 amino acid sequence of PF16 indicate that the protein contains eight contiguous armadillo repeats. A number of proteins with diverse cellular functions also contain armadillo repeats including pendulin, Rch1, importin, SRP-1, and armadillo. An antibody was raised against a fusion protein expressed from the cloned cDNA. Immunofluorescence labeling of wild-type flagella indicates that the PF16 protein is localized along the length of the flagella while immunogold labeling further localizes the PF16 protein to a single microtubule of the central pair. Based on the localization results and the presence of the armadillo repeats in this protein, we suggest that the PF16 gene product is involved in protein-protein interactions important for C1 central microtubule stability and flagellar motility.

Engineering an acetyllysine reader with photocrosslinking amino acid for interactome profiling

2021 ◽  
Author(s):  
Babu Sudhamalla ◽  
Anirban Roy ◽  
Soumen Barman ◽  
Jyotirmayee Padhan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Interactions ◽  
Unnatural Amino Acids ◽  
Protein Protein Interactions ◽  
Site Specific ◽  
Powerful Approach

The site-specific installation of light-activable crosslinker unnatural amino acids offers a powerful approach to trap transient protein-protein interactions both in vitro and in vivo. Herein, we engineer a bromodomain to...

Plakoglobin domains that define its association with the desmosomal cadherins and the classical cadherins: identification of unique and shared domains

1996 ◽  
Vol 109 (5) ◽  
pp. 1143-1154 ◽  
Author(s):  
J.K. Wahl ◽  
P.A. Sacco ◽  
T.M. McGranahan-Sadler ◽  
L.M. Sauppe ◽  
M.J. Wheelock ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Intermediate Filament ◽  
Adherens Junction ◽  
Cell Junctions ◽  
Central Domain ◽  
Desmosomal Cadherins ◽  
Cytoplasmic Proteins ◽  
C Terminus ◽  
Classical Cadherins ◽  
N Terminus

Two cell-cell junctions, the adherens junction and the desmosome, are prominent in epithelial cells. These junctions are composed of transmembrane cadherins which interact with cytoplasmic proteins that serve to link the cadherin to the cytoskeleton. One component of both adherens junctions and desmosomes is plakoglobin. In the adherens junction plakoglobin interacts with both the classical cadherin and with alpha-catenin. Alpha-catenin in turn interacts with microfilaments. The role plakoglobin plays in the desmosome is not well understood. Plakoglobin interacts with the desmosomal cadherins, but how and if this mediates interactions with the intermediate filament cytoskeleton is not known. Here we compare the domains of plakoglobin that allow it to associate with the desmosomal cadherins with those involved in interactions with the classical cadherins. We show that three sites on plakoglobin are involved in associations with the desmosomal cadherins. A domain near the N terminus is unique to the desmosomal cadherins and overlaps with the site that interacts with alpha-catenin, suggesting that there may be competition between alpha-catenin and the desmosomal cadherins for interactions with plakoglobin. In addition, a central domain is shared with regions used by plakoglobin to associate with the classical cadherins. Finally, a domain near the C terminus is shown to strongly modulate the interactions with the desmosomal cadherins. This latter domain also contributes to the association of plakoglobin with the classical cadherins.

scholarly journals Positive and Negative Regulation of Poly(A) Nuclease

2004 ◽  
Vol 24 (12) ◽  
pp. 5521-5533 ◽  
Author(s):  
David A. Mangus ◽  
Matthew C. Evans ◽  
Nathan S. Agrin ◽  
Mandy Smith ◽  
Preetam Gongidi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Interactions ◽  
Binding Pocket ◽  
Negative Regulation ◽  
Single Amino Acid ◽  
Carboxy Terminus ◽  
Protein Protein Interactions ◽  
C Terminus

ABSTRACT PAN, a yeast poly(A) nuclease, plays an important nuclear role in the posttranscriptional maturation of mRNA poly(A) tails. The activity of this enzyme is dependent on its Pan2p and Pan3p subunits, as well as the presence of poly(A)-binding protein (Pab1p). We have identified and characterized the associated network of factors controlling the maturation of mRNA poly(A) tails in yeast and defined its relevant protein-protein interactions. Pan3p, a positive regulator of PAN activity, interacts with Pab1p, thus providing substrate specificity for this nuclease. Pab1p also regulates poly(A) tail trimming by interacting with Pbp1p, a factor that appears to negatively regulate PAN. Pan3p and Pbp1p both interact with themselves and with the C terminus of Pab1p. However, the domains required for Pan3p and Pbp1p binding on Pab1p are distinct. Single amino acid changes that disrupt Pan3p interaction with Pab1p have been identified and define a binding pocket in helices 2 and 3 of Pab1p's carboxy terminus. The importance of these amino acids for Pab1p-Pan3p interaction, and poly(A) tail regulation, is underscored by experiments demonstrating that strains harboring substitutions in these residues accumulate mRNAs with long poly(A) tails in vivo.

scholarly journals Structure/Function Analysis of the Vaccinia Virus F18 Phosphoprotein, an Abundant Core Component Required for Virion Maturation and Infectivity

2010 ◽  
Vol 84 (13) ◽  
pp. 6846-6860 ◽  
Author(s):  
Nadi T. Wickramasekera ◽  
Paula Traktman
Keyword(s):  
Amino Acids ◽  
Structure Function ◽  
Protein Interactions ◽  
Function Analysis ◽  
Aromatic Amino Acids ◽  
Protein Protein Interactions ◽  
Core Component ◽  
Virion Morphogenesis

ABSTRACT Poxvirus virions, whose outer membrane surrounds two lateral bodies and a core, contain at least 70 different proteins. The F18 phosphoprotein is one of the most abundant core components and is essential for the assembly of mature virions. We report here the results of a structure/function analysis in which the role of conserved cysteine residues, clusters of charged amino acids and clusters of hydrophobic/aromatic amino acids have been assessed. Taking advantage of a recombinant virus in which F18 expression is IPTG (isopropyl-β-d-thiogalactopyranoside) dependent, we developed a transient complementation assay to evaluate the ability of mutant alleles of F18 to support virion morphogenesis and/or to restore the production of infectious virus. We have also examined protein-protein interactions, comparing the ability of mutant and WT F18 proteins to interact with WT F18 and to interact with the viral A30 protein, another essential core component. We show that F18 associates with an A30-containing multiprotein complex in vivo in a manner that depends upon clusters of hydrophobic/aromatic residues in the N′ terminus of the F18 protein but that it is not required for the assembly of this complex. Finally, we confirmed that two PSSP motifs within F18 are the sites of phosphorylation by cellular proline-directed kinases in vitro and in vivo. Mutation of both of these phosphorylation sites has no apparent impact on virion morphogenesis but leads to the assembly of virions with significantly reduced infectivity.

scholarly journals Amalgamation of 3D structure and sequence information for protein–protein interaction prediction

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kanchan Jha ◽  
Sriparna Saha
Keyword(s):  
Amino Acids ◽  
Deep Learning ◽  
Protein Interactions ◽  
3D Structure ◽  
Protein Sequences ◽  
Building Blocks ◽  
New Drugs ◽  
Sequence Information ◽  
Protein Protein Interactions ◽  
Structure Information

Abstract Protein is the primary building block of living organisms. It interacts with other proteins and is then involved in various biological processes. Protein–protein interactions (PPIs) help in predicting and hence help in understanding the functionality of the proteins, causes and growth of diseases, and designing new drugs. However, there is a vast gap between the available protein sequences and the identification of protein–protein interactions. To bridge this gap, researchers proposed several computational methods to reveal the interactions between proteins. These methods merely depend on sequence-based information of proteins. With the advancement of technology, different types of information related to proteins are available such as 3D structure information. Nowadays, deep learning techniques are adopted successfully in various domains, including bioinformatics. So, current work focuses on the utilization of different modalities, such as 3D structures and sequence-based information of proteins, and deep learning algorithms to predict PPIs. The proposed approach is divided into several phases. We first get several illustrations of proteins using their 3D coordinates information, and three attributes, such as hydropathy index, isoelectric point, and charge of amino acids. Amino acids are the building blocks of proteins. A pre-trained ResNet50 model, a subclass of a convolutional neural network, is utilized to extract features from these representations of proteins. Autocovariance and conjoint triad are two widely used sequence-based methods to encode proteins, which are used here as another modality of protein sequences. A stacked autoencoder is utilized to get the compact form of sequence-based information. Finally, the features obtained from different modalities are concatenated in pairs and fed into the classifier to predict labels for protein pairs. We have experimented on the human PPIs dataset and Saccharomyces cerevisiae PPIs dataset and compared our results with the state-of-the-art deep-learning-based classifiers. The results achieved by the proposed method are superior to those obtained by the existing methods. Extensive experimentations on different datasets indicate that our approach to learning and combining features from two different modalities is useful in PPI prediction.

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