scholarly journals The molecular regulation of Janus kinase (JAK) activation

2014 ◽  
Vol 462 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Jeffrey J. Babon ◽  
Isabelle S. Lucet ◽  
James M. Murphy ◽  
Nicos A. Nicola ◽  
Leila N. Varghese
Keyword(s):  
Tyrosine Kinase ◽  
Kinase Inhibitors ◽  
Current Knowledge ◽  
Inflammatory Diseases ◽  
Sh2 Domain ◽  
Janus Kinase ◽  
Causative Role ◽  
Tyrosine Kinase 2 ◽  
Src Homology

The JAK (Janus kinase) family members serve essential roles as the intracellular signalling effectors of cytokine receptors. This family, comprising JAK1, JAK2, JAK3 and TYK2 (tyrosine kinase 2), was first described more than 20 years ago, but the complexities underlying their activation, regulation and pleiotropic signalling functions are still being explored. Here, we review the current knowledge of their physiological functions and the causative role of activating and inactivating JAK mutations in human diseases, including haemopoietic malignancies, immunodeficiency and inflammatory diseases. At the molecular level, recent studies have greatly advanced our knowledge of the structures and organization of the component FERM (4.1/ezrin/radixin/moesin)-SH2 (Src homology 2), pseudokinase and kinase domains within the JAKs, the mechanism of JAK activation and, in particular, the role of the pseudokinase domain as a suppressor of the adjacent tyrosine kinase domain's catalytic activity. We also review recent advances in our understanding of the mechanisms of negative regulation exerted by the SH2 domain-containing proteins, SOCS (suppressors of cytokine signalling) proteins and LNK. These recent studies highlight the diversity of regulatory mechanisms utilized by the JAK family to maintain signalling fidelity, and suggest alternative therapeutic strategies to complement existing ATP-competitive kinase inhibitors.

scholarly journals Selective Tyrosine Kinase 2 Inhibition for Treatment of Inflammatory Bowel Disease: New Hope on the Rise

2021 ◽  
Author(s):  
Silvio Danese ◽  
Laurent Peyrin-Biroulet
Keyword(s):  
Inflammatory Bowel Disease ◽  
Tyrosine Kinase ◽  
Bowel Disease ◽  
Inflammatory Diseases ◽  
Janus Kinase ◽  
Type I ◽  
Tyrosine Kinase 2 ◽  
Immune Mediated ◽  
Inflammatory Bowel

Abstract Conventional systemic and biologic agents are the mainstay of inflammatory bowel disease (IBD) management; however, many of these agents are associated with loss of clinical response, highlighting the need for effective, novel targeted therapies. Janus kinase (JAK) 1-3 and tyrosine kinase 2 (TYK2) mediate signal transduction events downstream of multiple cytokine receptors that regulate targeted gene transcription, including the interleukin-12, interleukin-23, and type I interferon receptors for TYK2. This review summarizes the role of TYK2 signaling in IBD pathogenesis, the differential selectivity of TYK2 inhibitors, and the potential clinical implications of TYK2 inhibition in IBD. A PubMed literature review was conducted to identify studies of JAK1-3 and TYK2 inhibitors in IBD and other immune-mediated inflammatory diseases. Key efficacy and safety information was extracted and summarized. Pan-JAK inhibitors provide inconsistent efficacy in patients with IBD and are associated with toxicities resulting from a lack of selectivity at therapeutic dosages. Selective inhibition of TYK2 signaling via an allosteric mechanism, with an agent that binds to the regulatory (pseudokinase) domain, may reduce potential toxicities typically associated with JAK1-3 inhibitors. Deucravacitinib, a novel, oral, selective TYK2 inhibitor, and brepocitinib and PF-06826647, TYK2 inhibitors that bind to the active site in the catalytic domain, are in development for IBD and other immune-mediated inflammatory diseases. Allosteric TYK2 inhibition is more selective than JAK1-3 inhibition and has the potential to limit toxicities typically associated with JAK1-3 inhibitors. Future studies will be important in establishing the role of selective, allosteric TYK2 inhibition in the management of IBD.

A REVIEW ON THE ROLE OF TYROSINE KINASE INHIBITORS AVAILABLE FOR THE MANAGEMENT OF CHRONIC MYELOID LEUKEMIA

2020 ◽  
Vol 7 (2) ◽  
pp. 205-211
Author(s):  
Kaynat Fatima ◽  
Syed Tasleem Raza ◽  
Ale Eba ◽  
Sanchita Srivastava ◽  
Farzana Mahdi
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Protein Kinases ◽  
Tyrosine Kinase Inhibitors ◽  
Myeloid Leukemia ◽  
Kinase Inhibitors ◽  
Line Treatment ◽  
First Line ◽  
First Line Treatment

The function of protein kinases is to transfer a γ-phosphate group from ATP to serine, threonine, or tyrosine residues. Many of these kinases are linked to the initiation and development of human cancer. The recent development of small molecule kinase inhibitors for the treatment of different types of cancer in clinical therapy has proven successful. Significantly, after the G-protein-coupled receptors, protein kinases are the second most active category of drug targets. Imatinib mesylate was the first tyrosine kinase inhibitor (TKI), approved for chronic myeloid leukemia (CML) treatment. Imatinib induces appropriate responses in ~60% of patients; with ~20% discontinuing therapy due to sensitivity, and ~20% developing drug resistance. The introduction of newer TKIs such as, nilotinib, dasatinib, bosutinib, and ponatinib has provided patients with multiple options. Such agents are more active, have specific profiles of side effects and are more likely to reach the necessary milestones. First-line treatment decisions must be focused on CML risk, patient preferences and comorbidities. Given the excellent result, half of the patients eventually fail to seek first-line treatment (due to discomfort or resistance), with many of them needing a third or even further therapy lines. In the present review, we will address the role of tyrosine kinase inhibitors in therapy for chronic myeloid leukemia.

scholarly journals Proline-rich tyrosine kinase 2 mediates transforming growth factor-beta-induced hepatic stellate cell activation and liver fibrosis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jonghwa Kim ◽  
Wonseok Kang ◽  
So Hee Kang ◽  
Su Hyun Park ◽  
Ji Young Kim ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Tyrosine Kinase ◽  
Focal Adhesion ◽  
Transforming Growth Factor ◽  
Family Members ◽  
Type I ◽  
Tyrosine Kinase 2 ◽  
The Impact ◽  
Tgf Β1

AbstractHepatic fibrogenesis is characterized by activation of hepatic stellate cells (HSCs) and accumulation of extracellular matrix (ECM). The impact of ECM on TGF-β-mediated fibrogenic signaling pathway in HSCs has remained obscure. We studied the role of non-receptor tyrosine kinase focal adhesion kinase (FAK) family members in TGF-β-signaling in HSCs. We used a CCl4-induced liver fibrosis mice model to evaluate the effect of FAK family kinase inhibitors on liver fibrosis. RT-PCR and Western blot were used to measure the expression of its target genes; α-SMA, collagen, Nox4, TGF-β1, Smad7, and CTGF. Pharmacological inhibitors, siRNA-mediated knock-down, and plasmid-based overexpression were adopted to modulate the function and the expression level of proteins. Association of PYK2 activation with liver fibrosis was confirmed in liver samples from CCl4-treated mice and patients with significant fibrosis or cirrhosis. TGF-β treatment up-regulated expression of α-SMA, type I collagen, NOX4, CTGF, TGF-β1, and Smad7 in LX-2 cells. Inhibition of FAK family members suppressed TGF-β-mediated fibrogenic signaling. SiRNA experiments demonstrated that TGF-β1 and Smad7 were upregulated via Smad-dependent pathway through FAK activation. In addition, CTGF induction was Smad-independent and PYK2-dependent. Furthermore, RhoA activation was essential for TGF-β-mediated CTGF induction, evidenced by using ROCK inhibitor and dominant negative RhoA expression. We identified that TGF-β1-induced activation of PYK2-Src-RhoA triad leads to YAP/TAZ activation for CTGF induction in liver fibrosis. These findings provide new insights into the role of focal adhesion molecules in liver fibrogenesis, and targeting PYK2 may be an attractive target for developing novel therapeutic strategies for the treatment of liver fibrosis.

scholarly journals Potential role of tyrosine kinase inhibitors during primary HIV-1 infection

2017 ◽  
Vol 15 (5) ◽  
pp. 421-423 ◽  
Author(s):  
Juan Ambrosioni ◽  
Mayte Coiras ◽  
José Alcamí ◽  
José M. Miró
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitors ◽  
Potential Role ◽  
Kinase Inhibitors ◽  
Hiv 1

scholarly journals Emerging role of tyrosine kinase inhibitors in the treatment of advanced renal cell cancer: a review

2006 ◽  
Vol 17 (8) ◽  
pp. 1185-1196 ◽  
Author(s):  
P. Schöffski ◽  
H. Dumez ◽  
P. Clement ◽  
A. Hoeben ◽  
H. Prenen ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitors ◽  
Renal Cell Cancer ◽  
Renal Cell ◽  
Kinase Inhibitors ◽  
Cell Cancer ◽  
Advanced Renal Cell Cancer
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