Identification of small-molecule inhibitors of the JIP–JNK interaction

2009 ◽  
Vol 420 (2) ◽  
pp. 283-296 ◽  
Author(s):  
Tracy Chen ◽  
Natasha Kablaoui ◽  
Jeremy Little ◽  
Sergei Timofeevski ◽  
William R. Tschantz ◽  
...  

JNK1 (c-Jun N-terminal kinase 1) plays a crucial role in the regulation of obesity-induced insulin resistance and is implicated in the pathology of Type 2 diabetes. Its partner, JIP1 (JNK-interacting protein 1), serves a scaffolding function that facilitates JNK1 activation by MKK4 [MAPK (mitogen-activated protein kinase) kinase 4] and MKK7 (MAPK kinase 7). For example, reduced insulin resistance and JNK activation are observed in JIP1-deficient mice. On the basis of the in vivo efficacy of a cell-permeable JIP peptide, the JIP–JNK interaction appears to be a potential target for JNK inhibition. The goal of the present study was to identify small-molecule inhibitors that disrupt the JIP–JNK interaction to provide an alternative approach for JNK inhibition to ATP-competitive inhibitors. High-throughput screening was performed by utilizing a fluorescence polarization assay that measured the binding of JNK1 to the JIP peptide. Multiple chemical series were identified, revealing two categories of JIP/JNK inhibitors: ‘dual inhibitors’ that are ATP competitive and probably inhibit JIP–JNK binding allosterically, and ‘JIP-site binders’ that block binding through interaction with the JIP site. A series of polychloropyrimidines from the second category was characterized by biochemical methods and explored through medicinal-chemistry efforts. As predicted, these inhibitors also inhibited full-length JIP–JNK binding and were selective against a panel of 34 representative kinases, including ones in the MAPK family. Overall, this work demonstrates that small molecules can inhibit protein–protein interactions in vitro in the MAPK family effectively and provides strategies for similar approaches within other target families.

2020 ◽  
Vol 25 (9) ◽  
pp. 985-999
Author(s):  
John Vincent ◽  
Marian Preston ◽  
Elizabeth Mouchet ◽  
Nicolas Laugier ◽  
Adam Corrigan ◽  
...  

Cytoplasmic dynein-1 (hereafter dynein) is a six-subunit motor complex that transports a variety of cellular components and pathogens along microtubules. Dynein’s cellular functions are only partially understood, and potent and specific small-molecule inhibitors and activators of this motor would be valuable for addressing this issue. It has also been hypothesized that an inhibitor of dynein-based transport could be used in antiviral or antimitotic therapy, whereas an activator could alleviate age-related neurodegenerative diseases by enhancing microtubule-based transport in axons. Here, we present the first high-throughput screening (HTS) assay capable of identifying both activators and inhibitors of dynein-based transport. This project is also the first collaborative screening report from the Medical Research Council and AstraZeneca agreement to form the UK Centre for Lead Discovery. A cellular imaging assay was used, involving chemically controlled recruitment of activated dynein complexes to peroxisomes. Such a system has the potential to identify molecules that affect multiple aspects of dynein biology in vivo. Following optimization of key parameters, the assay was developed in a 384-well format with semiautomated liquid handling and image acquisition. Testing of more than 500,000 compounds identified both inhibitors and activators of dynein-based transport in multiple chemical series. Additional analysis indicated that many of the identified compounds do not affect the integrity of the microtubule cytoskeleton and are therefore candidates to directly target the transport machinery.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
James O’Connell ◽  
John Porter ◽  
Boris Kroeplien ◽  
Tim Norman ◽  
Stephen Rapecki ◽  
...  

AbstractTumour necrosis factor (TNF) is a cytokine belonging to a family of trimeric proteins; it has been shown to be a key mediator in autoimmune diseases such as rheumatoid arthritis and Crohn’s disease. While TNF is the target of several successful biologic drugs, attempts to design small molecule therapies directed to this cytokine have not led to approved products. Here we report the discovery of potent small molecule inhibitors of TNF that stabilise an asymmetrical form of the soluble TNF trimer, compromising signalling and inhibiting the functions of TNF in vitro and in vivo. This discovery paves the way for a class of small molecule drugs capable of modulating TNF function by stabilising a naturally sampled, receptor-incompetent conformation of TNF. Furthermore, this approach may prove to be a more general mechanism for inhibiting protein–protein interactions.


2005 ◽  
Vol 389 (1) ◽  
pp. 127-135 ◽  
Author(s):  
Claire E. EYERS ◽  
Helen McNEILL ◽  
Axel KNEBEL ◽  
Nick MORRICE ◽  
Simon J. C. ARTHUR ◽  
...  

A protein expressed in immune cells and muscle was detected in muscle extracts as a substrate for several SAPKs (stress-activated protein kinases). It interacted specifically with the F-actin capping protein CapZ in splenocytes, and was therefore termed ‘CapZIP’ (CapZ-interacting protein). Human CapZIP was phosphorylated at Ser-179 and Ser-244 by MAPKAP-K2 (mitogen-activated protein kinase-activated protein kinase 2) or MAPKAP-K3 in vitro. Anisomycin induced the phosphorylation of CapZIP at Ser-179 in Jurkat cells, which was prevented by SB 203580, consistent with phosphorylation by MAPKAP-K2 and/or MAPKAP-K3. However, osmotic shock-induced phosphorylation of Ser-179 was unaffected by SB 203580. These and other results suggest that CapZIP is phosphorylated at Ser-179 in cells by MAPKAP-K2/MAPKAP-K3, and at least one other protein kinase. Stress-activated MAP kinase family members phosphorylated human CapZIP at many sites, including Ser-68, Ser-83, Ser-108 and Ser-216. Ser-108 became phosphorylated when Jurkat cells were exposed to osmotic shock, which was unaffected by SB 203580 and/or PD 184352, or in splenocytes from mice that do not express either SAPK3/p38γ or SAPK4/p38δ. Our results suggest that CapZIP may be phosphorylated by JNK (c-Jun N-terminal kinase), which phosphorylates CapZIP to >5 mol/mol within minutes in vitro. Osmotic shock or anisomycin triggered the dissociation of CapZIP from CapZ in Jurkat cells, suggesting that phosphorylation of CapZIP may regulate the ability of CapZ to remodel actin filament assembly in vivo.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 306-306
Author(s):  
Meredith W. Miller ◽  
Soni Basra ◽  
Paul C. Billings ◽  
Jamie Gewirtz ◽  
William F. DeGrado ◽  
...  

Abstract Vascular damage due to trauma or disease exposes circulating platelets to collagen in the subendothelial matrix. This is a critical event in the formation of a hemostatic plug or an occluding thrombus because collagen is not only a substrate for platelet adhesion but is also a strong platelet agonist. Platelets possess two physiologic collagen receptors: glycoprotein VI, a member of the immunoglobin superfamily, and the integrin α2β1. To design small molecule inhibitors of the interaction of platelets with collagen, we focused on α2β1 as a target because murine models of α2β1 deficiency display normal bleeding times and only a slight decrease in platelet activation by collagen and because the small number of reported patients with congenital α2β1 deficiency demonstrated only a mild bleeding diathesis. Thus, α2β1 antagonists could be effective anti-thrombotic agents with minimal toxicity, especially when combined with other anti-platelet drugs. We have developed a class of compounds that target the I-like domain of the β1 subunit, an allosteric site that regulates collagen binding to α2β1 by preventing the conversion of α2β1 from an inactive (low affinity) to an active (high affinity) conformation. This class of compounds is based on a proline-substituted 2,3-diaminopropionic acid scaffold. Structure-activity relationship studies of the scaffold have focused on optimization of the proline moiety, the urea functionality, and the sulfonyl group and have resulted in the development of potent inhibitors of α2β1-mediated platelet adhesion to collagen with IC50’s in the high picomolar to low nanomolar range. In particular, optimization of the proline moiety lead to compounds with high potency: transitioning from proline (DB496, IC50 of 29–62 nM) to a thiazolidine (SB68A) improved the IC50 to 2–8 nM; adding a methyl group at the 2 position of the thiazolidine (SB68B) slightly improved the IC50 to 1–12 nM; adding two methyl groups at the 5 position of the thiazolidine (SW4-161) resulted in a lead compound with an IC50 of 0.33–8 nM. As expected, the compounds had no effect on the binding of isolated α2 I-domains to collagen, consistent with their I-like domain mode of activity. Further, they were specific for α2β1-mediated platelet adhesion to collagen because they had no impact on ADP-stimulated platelet aggregation when added at 2 μM, a concentration more than 100-fold greater than the IC50 for inhibition of platelet adhesion to collagen. The compounds were also strong inhibitors of murine platelet adhesion to collagen and when tested in the ferric chloride-initiated murine carotid artery injury model, displayed activity similar to aspirin. Thus, 71% of untreated mice in this thrombosis model developed occlusive thrombi that remained stable for the 30 min duration of the assay, whereas stable thrombi developed in only 32% of mice treated with 1g/kg aspirin orally and in 41% of mice receiving 60 mg/kg CSW4-161intravenously. In summary, we have developed a class of potent inhibitors of the integrin α2β1 that demonstrate both in vitro and in vivo anti-platelet activity. Further development of this class of compounds may result in novel and relatively non-toxic anti-thrombotic agents.


2011 ◽  
Vol 300 (1) ◽  
pp. 30-39 ◽  
Author(s):  
Pramod P. Mehta ◽  
Pei-Pei Kung ◽  
Shinji Yamazaki ◽  
Marlena Walls ◽  
Andrea Shen ◽  
...  

Neoplasia ◽  
2010 ◽  
Vol 12 (4) ◽  
pp. 326-IN6 ◽  
Author(s):  
Rajesh Kumar Gandhirajan ◽  
Peter Anton Staib ◽  
Katharina Minke ◽  
Iris Gehrke ◽  
Günther Plickert ◽  
...  

2018 ◽  
Vol 2 (6) ◽  
pp. 597-606 ◽  
Author(s):  
Danuta Jarocha ◽  
Karen K. Vo ◽  
Randolph B. Lyde ◽  
Vincent Hayes ◽  
Rodney M. Camire ◽  
...  

Key PointsDrugs shown to enhance megakaryocyte ploidy and size variably effect terminal injury and apoptosis of in vitro–grown megakaryocytes. The number of functional platelets released in vivo from infused megakaryocytes can be enhanced by these drug treatments.


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