scholarly journals Elucidation of protein-protein interactions necessary for maintenance of the BCR-ABL signaling complex

2019 ◽  
Author(s):  
Tomas Gregor ◽  
Michaela Kunova Bosakova ◽  
Alexandru Nita ◽  
Sara P. Abraham ◽  
Bohumil Fafilek ◽  
...  

AbstractApproximately 50% of chronic myeloid leukemia (CML) patients in deep remission experience a return of clinical CML after withdrawal of tyrosine kinase inhibitors (TKIs). This suggests signaling of inactive BCR-ABL, which allows for survival of cancer cells, leading to relapse. Understanding the dynamics of BCR-ABL signaling complex holds a key to the mechanism of BCR-ABL signaling. Here, we demonstrate that TKIs inhibit catalytic activity of BCR-ABL, but do not dissolve the BCR-ABL core signaling complex consisting of CrkL, SHC1, Grb2, SOS1, cCbl, and SHIP2. We show that CrkL binds to proline-rich regions located in C-terminal, intrinsically disordered region of BCR-ABL, that deletion of pleckstrin homology domain of BCR-ABL diminishes interaction with SHC1, and that BCR-ABL sequence motif located in disordered region around phosphorylated tyrosine 177 mediates binding of at least three core complex members, the Grb2, SOS1 and cCbl. Introduction of Y177F substitution blocks association with Grb2, SOS1 and cCbl. Further, we identified SHIP2 binding sites within the src-homology and tyrosine kinase domains of BCR-ABL. We found that BCR-ABL is unable to phosphorylate SHC1 in cells lacking SHIP2. Reintroducing SHIP2 into Ship2 knock-out cells restored SHC1 phosphorylation, which depended on inositol phosphatase activity of SHIP2. Our findings provide characterization of protein-protein interactions in the BCR-ABL signaling complex, and support the concept of targeting BCR-ABL signaling in CML by inhibition of its interactions with the members of the core complex.

2020 ◽  
Author(s):  
Annika Frauenstein ◽  
Stefan Ebner ◽  
Ankit Sinha ◽  
Kshiti Phulphagar ◽  
Kirby Swatek ◽  
...  

ABSTRACTCells signal through rearrangements of protein communities governed by covalent modifications and reversible interactions of distinct sets of proteins. A method that identifies those post-transcriptional modifications regulating signaling complex composition and functional phenotypes in one experimental setup would facilitate an efficient identification of novel molecular signaling checkpoints. Here we devised Modifications, Interactions and Phenotypes by Affinity Purification Mass Spectrometry (MIP-APMS), comprising the streamlined cloning and transduction of tagged proteins into functionalized reporter cells as well as affinity chromatography, followed by MS-based quantification. We report the time-resolved interplay of more than 50 previously undescribed modification and hundreds of protein-protein interactions of 19 immune protein complexes in monocytes. Validation of interdependecies between covalent, reversible and functional protein complex regulations by knock-out or site-specific mutation, revealed isgylation and phosphorylation of TRAF2 as well as ARHGEF18 interaction in Toll-like receptor 2 signaling. Moreover, we identify distinct mechanisms of action for small molecule inhibitors of p-38 (MAPK14). Our method provides a fast and cost-effective pipeline for the molecular interrogation of protein communities in diverse biological systems and primary cells.HighlightsExperimental framework to reveal dynamic signaling checkpoints in primary cellsIdentification of crosstalk between protein modifications and interactions in signaling complexesDiscovery of TRAF2 isgylation, phosphorylation and ARHGEF18 interaction in monocytesDifferential drug mode of action for p-38 (MAPK14) kinase inhibitorsGraphical abstract


2001 ◽  
Vol 276 (15) ◽  
pp. 12128-12134 ◽  
Author(s):  
Robynn V. Schillace ◽  
James W. Voltz ◽  
Alistair T. R. Sim ◽  
Shirish Shenolikar ◽  
John D. Scott

The phosphorylation status of cellular proteins is controlled by the opposing actions of protein kinases and phosphatases. Compartmentalization of these enzymes is critical for spatial and temporal control of these phosphorylation/dephosphorylation events. We previously reported that a 220-kDa A-kinase anchoring protein (AKAP220) coordinates the location of the cAMP-dependent protein kinase (PKA) and the type 1 protein phosphatase catalytic subunit (PP1c) (Schillace, R. V., and Scott, J. D. (1999)Curr. Biol.9, 321–324). We now demonstrate that an AKAP220 fragment is a competitive inhibitor of PP1c activity (Ki= 2.9 ± 0.7 μm). Mapping studies and activity measurements indicate that several protein-protein interactions act synergistically to inhibit PP1. A consensus targeting motif, between residues 1195 and 1198 (Lys-Val-Gln-Phe), binds but does not affect enzyme activity, whereas determinants between residues 1711 and 1901 inhibit the phosphatase. Analysis of truncated PP1c and chimeric PP1/2A catalytic subunits suggests that AKAP220 inhibits the phosphatase in a manner distinct from all known PP1 inhibitors and toxins. Intermolecular interactions within the AKAP220 signaling complex further contribute to PP1 inhibition as addition of the PKA regulatory subunit (RII) enhances phosphatase inhibition. These experiments indicate that regulation of PP1 activity by AKAP220 involves a complex network of intra- and intermolecular interactions.


2018 ◽  
Vol 1862 (6) ◽  
pp. 1283-1295 ◽  
Author(s):  
Patricia Santofimia-Castaño ◽  
Bruno Rizzuti ◽  
Olga Abián ◽  
Adrián Velázquez-Campoy ◽  
Juan L. Iovanna ◽  
...  

2020 ◽  
Vol 21 (10) ◽  
pp. 3709 ◽  
Author(s):  
Nathan W. Van Bibber ◽  
Cornelia Haerle ◽  
Roy Khalife ◽  
Bin Xue ◽  
Vladimir N. Uversky

Among the realm of repeat containing proteins that commonly serve as “scaffolds” promoting protein-protein interactions, there is a family of proteins containing between 2 and 20 tetratricopeptide repeats (TPRs), which are functional motifs consisting of 34 amino acids. The most distinguishing feature of TPR domains is their ability to stack continuously one upon the other, with these stacked repeats being able to affect interaction with binding partners either sequentially or in combination. It is known that many repeat-containing proteins are characterized by high levels of intrinsic disorder, and that many protein tandem repeats can be intrinsically disordered. Furthermore, it seems that TPR-containing proteins share many characteristics with hybrid proteins containing ordered domains and intrinsically disordered protein regions. However, there has not been a systematic analysis of the intrinsic disorder status of TPR proteins. To fill this gap, we analyzed 166 human TPR proteins to determine the degree to which proteins containing TPR motifs are affected by intrinsic disorder. Our analysis revealed that these proteins are characterized by different levels of intrinsic disorder and contain functional disordered regions that are utilized for protein-protein interactions and often serve as targets of various posttranslational modifications.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Javier A. Iserte ◽  
Tamas Lazar ◽  
Silvio C. E. Tosatto ◽  
Peter Tompa ◽  
Cristina Marino-Buslje

Abstract Intrinsically disordered proteins/regions (IDPs/IDRs) are crucial components of the cell, they are highly abundant and participate ubiquitously in a wide range of biological functions, such as regulatory processes and cell signaling. Many of their important functions rely on protein interactions, by which they trigger or modulate different pathways. Sequence covariation, a powerful tool for protein contact prediction, has been applied successfully to predict protein structure and to identify protein–protein interactions mostly of globular proteins. IDPs/IDRs also mediate a plethora of protein–protein interactions, highlighting the importance of addressing sequence covariation-based inter-protein contact prediction of this class of proteins. Despite their importance, a systematic approach to analyze the covariation phenomena of intrinsically disordered proteins and their complexes is still missing. Here we carry out a comprehensive critical assessment of coevolution-based contact prediction in IDP/IDR complexes and detail the challenges and possible limitations that emerge from their analysis. We found that the coevolutionary signal is faint in most of the complexes of disordered proteins but positively correlates with the interface size and binding affinity between partners. In addition, we discuss the state-of-art methodology by biological interpretation of the results, formulate evaluation guidelines and suggest future directions of development to the field.


2020 ◽  
Vol 19 (7) ◽  
pp. 1070-1075 ◽  
Author(s):  
Katrina Meyer ◽  
Matthias Selbach

Protein-protein interactions are often mediated by short linear motifs (SLiMs) that are located in intrinsically disordered regions (IDRs) of proteins. Interactions mediated by SLiMs are notoriously difficult to study, and many functionally relevant interactions likely remain to be uncovered. Recently, pull-downs with synthetic peptides in combination with quantitative mass spectrometry emerged as a powerful screening approach to study protein-protein interactions mediated by SLiMs. Specifically, arrays of synthetic peptides immobilized on cellulose membranes provide a scalable means to identify the interaction partners of many peptides in parallel. In this minireview we briefly highlight the relevance of SLiMs for protein-protein interactions, outline existing screening technologies, discuss unique advantages of peptide-based interaction screens and provide practical suggestions for setting up such peptide-based screens.


Biomolecules ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1084 ◽  
Author(s):  
Chana G. Sokolik ◽  
Nasrin Qassem ◽  
Jordan H. Chill

WASp-interacting protein (WIP), a regulator of actin cytoskeleton assembly and remodeling, is a cellular multi-tasker and a key member of a network of protein–protein interactions, with significant impact on health and disease. Here, we attempt to complement the well-established understanding of WIP function from cell biology studies, summarized in several reviews, with a structural description of WIP interactions, highlighting works that present a molecular view of WIP’s protein–protein interactions. This provides a deeper understanding of the mechanisms by which WIP mediates its biological functions. The fully disordered WIP also serves as an intriguing example of how intrinsically disordered proteins (IDPs) exert their function. WIP consists of consecutive small functional domains and motifs that interact with a host of cellular partners, with a striking preponderance of proline-rich motif capable of interactions with several well-recognized binding partners; indeed, over 30% of the WIP primary structure are proline residues. We focus on the binding motifs and binding interfaces of three important WIP segments, the actin-binding N-terminal domain, the central domain that binds SH3 domains of various interaction partners, and the WASp-binding C-terminal domain. Beyond the obvious importance of a more fundamental understanding of the biology of this central cellular player, this approach carries an immediate and highly beneficial effect on drug-design efforts targeting WIP and its binding partners. These factors make the value of such structural studies, challenging as they are, readily apparent.


Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4705
Author(s):  
Adiran Garaizar ◽  
Ignacio Sanchez-Burgos ◽  
Rosana Collepardo-Guevara ◽  
Jorge R. Espinosa

Proteins containing intrinsically disordered regions (IDRs) are ubiquitous within biomolecular condensates, which are liquid-like compartments within cells formed through liquid–liquid phase separation (LLPS). The sequence of amino acids of a protein encodes its phase behaviour, not only by establishing the patterning and chemical nature (e.g., hydrophobic, polar, charged) of the various binding sites that facilitate multivalent interactions, but also by dictating the protein conformational dynamics. Besides behaving as random coils, IDRs can exhibit a wide-range of structural behaviours, including conformational switching, where they transition between alternate conformational ensembles. Using Molecular Dynamics simulations of a minimal coarse-grained model for IDRs, we show that the role of protein conformation has a non-trivial effect in the liquid–liquid phase behaviour of IDRs. When an IDR transitions to a conformational ensemble enriched in disordered extended states, LLPS is enhanced. In contrast, IDRs that switch to ensembles that preferentially sample more compact and structured states show inhibited LLPS. This occurs because extended and disordered protein conformations facilitate LLPS-stabilising multivalent protein–protein interactions by reducing steric hindrance; thereby, such conformations maximize the molecular connectivity of the condensed liquid network. Extended protein configurations promote phase separation regardless of whether LLPS is driven by homotypic and/or heterotypic protein–protein interactions. This study sheds light on the link between the dynamic conformational plasticity of IDRs and their liquid–liquid phase behaviour.


2017 ◽  
Vol 429 (18) ◽  
pp. 2790-2801 ◽  
Author(s):  
Alexander G. Kozlov ◽  
Min Kyung Shinn ◽  
Elizabeth A. Weiland ◽  
Timothy M. Lohman

2006 ◽  
Vol 26 (8) ◽  
pp. 2887-2900 ◽  
Author(s):  
Kit I. Tong ◽  
Yasutake Katoh ◽  
Hideki Kusunoki ◽  
Ken Itoh ◽  
Toshiyuki Tanaka ◽  
...  

ABSTRACT The expression of the phase 2 detoxification enzymes and antioxidant proteins is induced at the transcriptional level by Nrf2 and negatively regulated at the posttranslational level by Keap1 through protein-protein interactions with and subsequent proteolysis of Nrf2. We found that the Neh2 domain of Nrf2 is an intrinsically disordered but biologically active regulatory domain containing a 33-residue central α-helix followed by a mini antiparallel β-sheet. Isothermal calorimetry analysis indicated that one Neh2 molecule interacts with two molecules of Keap1 via two binding sites, the stronger binding ETGE motif and the weaker binding DLG motif. Nuclear magnetic resonance titration study showed that these two motifs of the Neh2 domain bind to an overlapping site on the bottom surface of the β-propeller structure of Keap1. In contrast, the central α-helix of the Neh2 domain does not have any observable affinity to Keap1, suggesting that this region may serve as a bridge connecting the two motifs for the association with the two β-propeller structures of a dimer of Keap1. Based on these observations, we propose that Keap1 recruits Nrf2 by the ETGE motif and that the DLG motif of the Neh2 domain locks its lysine-rich central α-helix in a correct position to benefit ubiquitin signaling.


Sign in / Sign up

Export Citation Format

Share Document