The many faces of Janus kinase

Matthew M Seavey1, Pawel Dobrzanski

  • 1Cephalon, Inc., Drug Discovery Research, 145 Brandywine Parkway, West Chester, PA 19380, USA. matthew.seavey@gmail.com

Biochemical Pharmacology
|January 3, 2012
PubMed

Insights

Janus kinase (JAK) inhibitors show promise for treating cancer and autoimmune diseases. This review covers JAK inhibitors, including JAK2, for various conditions like arthritis, cancer, and lupus.

Area of Science:

  • Immunology
  • Oncology
  • Pharmacology

Background:

  • Janus kinases (JAKs) are crucial for immune responses.
  • JAKs are implicated in the pathogenesis of inflammatory diseases and cancer.
  • The first JAK inhibitor, Jakafi® (ruxolitinib), is approved for myeloproliferative neoplasms.

Purpose of the Study:

  • To review the role of small molecule JAK inhibitors in treating cancer and autoimmune diseases.
  • To emphasize JAK2 inhibition for therapeutic applications.
  • To discuss the use of JAK inhibitors in various conditions.

Main Methods:

  • Review of existing literature on JAK kinase inhibitors.
  • Discussion of experimental and clinical data.
  • Analysis of therapeutic applications in oncology and autoimmune disorders.

Main Results:

  • JAK inhibitors are in late-stage clinical development for various diseases.
  • JAK2 is a key target for small molecule inhibitors.
  • JAK inhibitors show potential for treating solid tumors, hematological malignancies, lupus, arthritis, colitis, and other conditions.

Conclusions:

  • Small molecule JAK inhibitors represent a promising therapeutic strategy.
  • JAK inhibition can complement existing treatment programs for cancer and autoimmune diseases.
  • Further research and clinical application of JAK inhibitors are warranted.

Related Concept Videos

The JAK-STAT Signaling Pathway01:20

The JAK-STAT Signaling Pathway

Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as  SH2...
cAMP-dependent Protein Kinase Pathways01:25

cAMP-dependent Protein Kinase Pathways

Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
Protein Kinases and Phosphatases02:54

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein Kinases and Phosphatases02:54

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Interactions Between Signaling Pathways01:19

Interactions Between Signaling Pathways

Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...