UNDERSTANDING THE JNK PATHWAY: MECHANISMS, ROLES, AND ANYGENES® SOLUTIONS
The c-Jun N-terminal kinase JNK pathway, a key component of the mitogen-activated protein kinase (MAPK) signaling cascade, regulates critical cellular processes like proliferation, apoptosis, differentiation, innate and adaptive responses, migration, autophagy, and stress responses. This pathway is activated by various stimuli, including environmental stressors, inflammatory cytokines, and growth factors.
At AnyGenes®, we provide cutting-edge tools, including gene expression assays and pathway-focused qPCR arrays, to facilitate advanced research into the JNK pathway and its implications in health and disease.
The c-Jun N-terminal kinase (JNK) is a serine/threonine kinase encoded by three genes: JNK1, JNK2, and JNK3. These genes respectively encode three distinct isoforms of the mitogen-activated protein kinases: MAPK8, MAPK9, and MAPK10. Together, they form a critical part of the canonical mitogen-activated protein kinase (MAPK) family.
STRESS RESPONSE
JNK proteins are highly responsive to a variety of stress stimuli, such as UV radiation, bacterial and viral infections, heat shock, and osmotic or genotoxic stresses. Their ability to respond to such diverse challenges underscores their importance in cellular stress response mechanisms.
JNKs are also referred to as stress-activated protein kinases (SAPKs) due to their prominent role in orchestrating cellular responses to stress. This dual nomenclature highlights their essential function in maintaining cellular homeostasis under challenging conditions.
CONTEXT-DEPENDENT ACTIVATION OF TH JNK PATHWAY
The effects of c-Jun N-terminal kinase pathway activation depend on its context and duration. Transient activation often promotes cellular proliferation, while prolonged activation can lead to cell death, emphasizing the pathway’s dual role in cell survival and apoptosis.
MECHANISM OF JNK ACTIVATION
Activation of the c-Jun N-terminal kinase pathway begins with upstream signals, such as environmental stressors, growth factors, or cytokines. JNK kinase kinases (JNKKKs), such as ASK1, phosphorylate and activate JNK kinases (JNKKs). The MKK4 and MKK7 kinases (upstream MAPK2Ks) are key activators of JNK. They phosphorylate conserved Thr-Pro-Tyr (TPY) motifs, driving JNK activation.
Once activated, JNK phosphorylates a range of downstream target proteins, including the AP-1 family of transcription factors, activating transcription factors (ATF), and ETS-like protein Elk-1. These targets are critical for gene expression changes that mediate cellular responses to stress and injury.
RELATIONSHIP BETWEEN C-JUN N-TERMINAL KINASE PATHWAY AND DISEASES
The c-Jun N-terminal kinase (JNK) pathway plays a critical role in cell renewal and is implicated in the development of various diseases. These include cancers such as glioblastoma, ovarian cancer, melanoma, basal cell carcinoma, and squamous cell carcinoma, as well as neurodegenerative conditions like Alzheimer’s, Parkinson’s, and Huntington’s diseases. It is also involved in muscle wasting associated with cancer cachexia, psoriasis, and dermal fibrosis.
Research suggests that the c-Jun N-terminal kinase pathway has a dual role, acting as both a tumor suppressor and a cancer promoter depending on the cellular context. This duality makes the JNK signaling pathway a promising target for molecular cancer therapies, offering potential for innovative treatments tailored to its complex role in cancer progression.
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