scholarly journals Insulin signalling: putting the G- in protein-protein interactions

2004 ◽  
Vol 380 (1) ◽  
pp. e11-e12 ◽  
Author(s):  
Craig C. MALBON

Cell signalling via receptor tyrosine kinases, such as the insulin receptor, and via heterotrimeric G-proteins, such as Gαi, Gαs and Gαq family members, constitute two of most avidly studied paradigms in cell biology. That elements of these two populous signalling pathways must cross-talk to achieve proper signalling in the regulation of cell proliferation, differentiation and metabolism has been anticipated, but the evolution of our thinking and the analysis of such cross-talk have lagged behind the ever-expanding troupe of players and the recognition of multivalency as the rule, rather than the exception, in signalling biology. New insights have been provided by Kreuzer et al. in this issue of the Biochemical Journal, in which insulin is shown to provoke recruitment of Gαi-proteins to insulin-receptor-based complexes that can regulate the gain of insulin-receptor-catalysed autophosphorylation, a proximal point in the insulin-sensitive cascade of signalling. Understanding the convergence and cross-talk of signals from the receptor tyrosine kinases and G-protein-coupled receptor pathways in physical, spatial and temporal contexts will remain a major challenge of cell biology.

2013 ◽  
Vol 104 (2) ◽  
pp. 608a
Author(s):  
Peter Lanzerstorfer ◽  
Andrea Steininger ◽  
Shin Ichiro Takahashi ◽  
Otmar Höglinger ◽  
Julian Weghuber

2021 ◽  
Author(s):  
Raiha Tahir ◽  
Anil K Madugundu ◽  
Savita Udainiya ◽  
Jevon A. Cutler ◽  
Santosh Renuse ◽  
...  

Non-receptor tyrosine kinases represent an important class of signaling molecules which are involved in driving diverse cellular pathways. Although, the large majority have been well-studied in terms of their protein-binding partners, the interactomes of some of the key non-receptor tyrosine kinases such as TNK2 (also known as activated Cdc42-associated kinase 1 or ACK1) have not been systematically investigated. Aberrant expression and hyperphosphorylation of TNK2 has been implicated in a number of cancers. However, the exact proteins and cellular events that mediate phenotypic changes downstream of TNK2 are unclear. Biological systems that employ proximity-dependent biotinylation methods, such as BioID, are being increasingly used to map protein-protein interactions as they provide increased sensitivity in discovering interaction partners. In this study, we employed BioID coupled to the biotinylation site identification technology (BioSITe) method that we recently developed to perform molecular mapping of intracellular proteins associated with TNK2. We also employed stable isotope labeling with amino acids in cell culture (SILAC) to quantitatively explore the interactome of TNK2. By performing a controlled comparative analysis between full-length TNK2 and its truncated counterpart, we were not only able to confidently identify site-level biotinylation of previously well-established TNK2 binders and substrates such as NCK1, NCK2, CTTN, STAT3, but also discover several novel TNK2 interacting partners. We validated TNK2 interaction with one of the novel TNK2 interacting protein, clathrin interactor 1 (CLINT1), using immunoblot analysis. Overall, this work reveals the power of the BioSITe method coupled to BioID and highlights several molecules that warrant further exploration to assess their functional significance in TNK2-mediated signaling.


2000 ◽  
Vol 20 (13) ◽  
pp. 4708-4723 ◽  
Author(s):  
Günter Müller ◽  
Susanne Wied ◽  
Wendelin Frick

ABSTRACT Signaling molecules downstream from the insulin receptor, such as the insulin receptor substrate protein 1 (IRS-1), are also activated by other receptor tyrosine kinases. Here we demonstrate that the non-receptor tyrosine kinases, focal adhesion kinase pp125FAK and Src-class kinase pp59Lyn, after insulin-independent activation by phosphoinositolglycans (PIG), can cross talk to metabolic insulin signaling in rat and 3T3-L1 adipocytes. Introduction by electroporation of neutralizing antibodies against pp59Lyn and pp125FAK into isolated rat adipocytes blocked IRS-1 tyrosine phosphorylation in response to PIG but not insulin. Introduction of peptides encompassing either the major autophosphorylation site of pp125FAK, tyrosine 397, or its regulatory loop with the twin tyrosines 576 and 577 inhibited PIG-induced IRS-1 tyrosine phosphorylation and glucose transport. PIG-induced pp59Lyn kinase activation and pp125FAK tyrosine phosphorylation were impaired by the former and latter peptide, respectively. Up-regulation of pp125FAK by integrin clustering diminished PIG-induced IRS-1 tyrosine phosphorylation and glucose transport in nonadherent but not adherent adipocytes. In conclusion, PIG induced IRS-1 tyrosine phosphorylation by causing (integrin antagonized) recruitment of IRS-1 and pp59Lyn to the common signaling platform molecule pp125FAK, where cross talk of PIG-like structures and extracellular matrix proteins to metabolic insulin signaling may converge, possibly for the integration of the demands of glucose metabolism and cell architecture.


Genome ◽  
2016 ◽  
Vol 59 (7) ◽  
pp. 439-448 ◽  
Author(s):  
Siti W. Mohd-Zin ◽  
Nor-Linda Abdullah ◽  
Aminah Abdullah ◽  
Nicholas D.E. Greene ◽  
Pike-See Cheah ◽  
...  

The EphA4 receptor tyrosine kinase is involved in numerous cell-signalling activities during embryonic development. EphA4 has the ability to bind to both types of ephrin ligands, the ephrinAs and ephrinBs. The C57BL/6J-Epha4rb-2J/GrsrJ strain, denoted Epha4rb-2J/rb-2J, is a spontaneous mouse mutant that arose at The Jackson Laboratory. These mutants exhibited a synchronous hind limb locomotion defect or “hopping gait” phenotype, which is also characteristic of EphA4 null mice. Genetic complementation experiments suggested that Epha4rb-2J corresponds to an allele of EphA4, but details of the genomic defect in this mouse mutant are currently unavailable. We found a single base-pair deletion in exon 9 resulting in a frame shift mutation that subsequently resulted in a premature stop codon. Analysis of the predicted structure of the truncated protein suggests that both the kinase and sterile α motif (SAM) domains are absent. Definitive determination of genotype is needed for experimental studies of mice carrying the Epha4rb-2J allele, and we have also developed a method to ease detection of the mutation through RFLP. Eph-ephrin family members are reportedly expressed as numerous isoforms. Hence, delineation of the specific mutation in EphA4 in this strain is important for further functional studies, such as protein–protein interactions, immunostaining and gene compensatory studies, investigating the mechanism underlying the effects of altered function of Eph family of receptor tyrosine kinases on phenotype.


2005 ◽  
Vol 185 (1) ◽  
pp. 19-33 ◽  
Author(s):  
Andrew W Stoker

A cornerstone of many cell-signalling events rests on reversible phosphorylation of tyrosine residues on proteins. The reversibility relies on the coordinated actions of protein tyrosine kinases and protein tyrosine phosphatases (PTPs), both of which exist as large protein families. This review focuses on the rapidly evolving field of the PTPs. We now know that rather than simply scavenging phosphotyrosine, the PTPs specifically regulate a wide range of signalling pathways. To illustrate this and to highlight current areas of agreement and contention in the field, this review will present our understanding of PTP action in selected areas and will present current knowledge surrounding the regulatory mechanisms that control PTP enzymes themselves. It will be seen that PTPs control diverse processes such as focal adhesion dynamics, cell–cell adhesion and insulin signalling, and their own actions are in turn regulated by dimerisation, phosphorylation and reversible oxidation.


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.


2012 ◽  
Vol 443 (3) ◽  
pp. 627-634 ◽  
Author(s):  
Xin Lin ◽  
Xin Li ◽  
Ming Jiang ◽  
Linhai Chen ◽  
Chanjuan Xu ◽  
...  

Many GPCRs (G-protein-coupled receptors) can activate RTKs (receptor tyrosine kinases) in the absence of RTK ligands, a phenomenon called transactivation. However, the underlying molecular mechanisms remain undefined. In the present study we investigate the molecular basis of GABAB (γ-aminobutyric acid B) receptor-mediated transactivation of IGF-1R (insulin-like growth factor type I receptor) in primary neurons. We take a chemical biology approach by developing an activity-based probe targeting the GABAB receptor. This probe enables us first to lock the GABAB receptor in an inactive state and then activate it with a positive allosteric modulator, thereby permitting monitoring of the dynamic of the protein complex associated with IGF-1R transactivation. We find that activation of the GABAB receptor induces a dynamic assembly and disassembly of a protein complex, including both receptors and their downstream effectors. FAK (focal adhesion kinase), a non-RTK, plays a key role in co-ordinating this dynamic process. Importantly, this dynamic of the GABAB receptor-associated complex is critical for transactivation and transactivation-dependent neuronal survival. The present study has identified an important mechanism underlying GPCR transactivation of RTKs, which was enabled by a new chemical biology tool generally applicable for dissecting GPCR signalling.


1993 ◽  
Vol 340 (1293) ◽  
pp. 279-285 ◽  

The targets of receptor protein-tyrosine kinases are characterized by Src homology 2 (SH2) domains, that mediate specific interactions with receptor autophosphorylation sites. SH 2-mediated interactions are important for the activation of biochemical signalling pathways in cells stimulated with growth factors. A distinct protein module, the SH3 domain, is frequently found in polypeptides that contain SH2 domains, and is also implicated in controlling protein-protein interactions in signal transduction. Evidence suggesting that SH2 and SH3 domains act synergistically in stimulation of the Ras pathway is discussed.


2006 ◽  
Vol 84 (6) ◽  
pp. 912-917 ◽  
Author(s):  
Ray Truant ◽  
Randy Atwal ◽  
Anjee Burtnik

Huntington’s disease is a progressive neurodegenerative genetic disorder that is caused by a CAG triplet-repeat expansion in the first exon of the IT15 gene. This CAG expansion results in polyglutamine expansion in the 350 kDa huntingtin protein. The exact function of huntingtin is unknown. Understanding the pathological triggers of mutant huntingtin, and distinguishing the cause of disease from downstream effects, is critical to designing therapeutic strategies and defining long- and short-term goals of therapy. Many studies that have sought to determine the functions of huntingtin by determining huntingtin’s protein–protein interactions have been published. Through these studies, huntingtin has been seen to interact with a large number of proteins, and is likely a scaffolding protein for protein–protein interactions. Recently, using imaging, integrative proteomics, and cell biology, huntingtin has been defined as a membrane-associated protein, with activities related to axonal trafficking of vesicles and mitochondria. These functions have also been attributed to some huntingtin-interacting proteins. Additionally, discoveries of a membrane association domain and a palmitoylation site in huntingtin reinforce the fact that huntingtin is membrane associated. In Huntington’s disease mouse and fly models, axonal vesicle trafficking is inhibited, and lack of proper uptake of neurotrophic factors may be an important pathological trigger leading to striatal cell death in Huntington’s disease. Here we discuss recent advances from many independent groups and methodologies that are starting to resolve the elusive function of huntingtin in vesicle transport, and evidence that suggests that huntingtin may be directly involved in membrane interactions.


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