JNK1, also known as mitogen-activated protein kinase 8 – MAPK8, is a serine/threonine-protein kinase. It is an important player in signaling transduction pathways governing cellular response to external stimuli, including ultraviolet radiation (UV), inflammatory cytokines, and reactive oxygen species (ROS). JNK1 phosphorylates several transcription factors, such as c-Jun, Elk-1, and ATF2, affecting their transcription activity.
JNK1 is ubiquitously expressed.
Involvement in disease
There are four isoforms of JNK1 (PMID: 8654373), giving rise to 46 kDa and 55 kDa isoforms. JNK1 isoforms differ in their substrate specificity and tissue expression profiles.
JNK1 is phosphorylated by MAPK kinases (MAPKK).
JNK1 is present both in the nucleus and in the cytoplasm. Stress conditions and other stimuli can cause a shift in JNK1 subcellular distribution.