Mitogen-activated protein kinase 8 (also known as JNK1) is a ubiquitous enzyme that in humans is encoded by the MAPK8 gene. [5] [6]
The protein encoded by this gene is a member of the MAP kinase and JNK family. MAP kinases act as an integration point for multiple biochemical signals, and are involved in a wide variety of cellular processes such as proliferation, differentiation, transcription regulation and development. This kinase is activated by various cell stimuli, and targets specific transcription factors, and thus mediates immediate-early gene expression in response to cell stimuli. The activation of this kinase by tumor-necrosis factor alpha (TNF-alpha) is found to be required for TNF-alpha-induced apoptosis. This kinase is also involved in UV radiation-induced apoptosis, which is thought to be related to the cytochrome c-mediated cell death pathway. Studies of the mouse counterpart of this gene suggested that this kinase play a key role in T cell proliferation, apoptosis and differentiation. Four alternately spliced transcript variants encoding distinct isoforms have been reported. [7] MAPK8 contains multiple amino acid sites that are phosphorylated and ubiquitinated. [8]
MAPK8 has been shown to interact with:
c-Jun N-terminal kinases (JNKs), were originally identified as kinases that bind and phosphorylate c-Jun on Ser-63 and Ser-73 within its transcriptional activation domain. They belong to the mitogen-activated protein kinase family, and are responsive to stress stimuli, such as cytokines, ultraviolet irradiation, heat shock, and osmotic shock. They also play a role in T cell differentiation and the cellular apoptosis pathway. Activation occurs through a dual phosphorylation of threonine (Thr) and tyrosine (Tyr) residues within a Thr-Pro-Tyr motif located in kinase subdomain VIII. Activation is carried out by two MAP kinase kinases, MKK4 and MKK7, and JNK can be inactivated by Ser/Thr and Tyr protein phosphatases. It has been suggested that this signaling pathway contributes to inflammatory responses in mammals and insects.
Mitogen-activated protein kinase 9 is an enzyme that in humans is encoded by the MAPK9 gene.
Mitogen-activated protein kinase 1, also known as ERK2, is an enzyme that in humans is encoded by the MAPK1 gene.
Dual specificity mitogen-activated protein kinase kinase 1 is an enzyme that in humans is encoded by the MAP2K1 gene.
Dual-specificity mitogen-activated protein kinase kinase 4 is an enzyme that in humans is encoded by the MAP2K4 gene.
Dual specificity mitogen-activated protein kinase kinase 3 is an enzyme that in humans is encoded by the MAP2K3 gene.
C-jun-amino-terminal kinase-interacting protein 1 is an enzyme that in humans is encoded by the MAPK8IP1 gene.
Mitogen-activated protein kinase kinase kinase 11 is an enzyme that in humans is encoded by the MAP3K11 gene.
Activating transcription factor 2, also known as ATF2, is a protein that, in humans, is encoded by the ATF2 gene.
Dual specificity mitogen-activated protein kinase kinase 7, also known as MAP kinase kinase 7 or MKK7, is an enzyme that in humans is encoded by the MAP2K7 gene. This protein is a member of the mitogen-activated protein kinase kinase family. The MKK7 protein exists as six different isoforms with three possible N-termini and two possible C-termini.
Ribosomal protein S6 kinase alpha-5 is an enzyme that in humans is encoded by the RPS6KA5 gene. This kinase, together with RPS6KA4, are thought to mediate the phosphorylation of histone H3, linked to the expression of immediate early genes.
C-jun-amino-terminal kinase-interacting protein 3 is an enzyme that in humans is encoded by the MAPK8IP3 gene.
Mitogen-activated protein kinase kinase kinase 4 is an enzyme that in humans is encoded by the MAP3K4 gene.
Mitogen-activated protein kinase kinase kinase 10 is an enzyme that in humans is encoded by the MAP3K10 gene.
Mitogen-Activated Protein Kinase Kinase Kinase 2 also known as MEKK2 is an enzyme that in humans is encoded by the MAP3K2 gene.
Mitogen-activated protein kinase 12 is an enzyme that in humans is encoded by the MAP3K12 gene.
C-jun-amino-terminal kinase-interacting protein 2 is a protein or the name of the gene that encodes it. The gene is also known as Islet-Brain-2 (IB2).
Serine/threonine-protein kinase VRK1 is an enzyme that in humans is encoded by the VRK1 gene.
Mitogen-activated protein kinase 11 is an enzyme that in humans is encoded by the MAPK11 gene.
Mitogen-activated protein kinase 10 also known as c-Jun N-terminal kinase 3 (JNK3) is an enzyme that in humans is encoded by the MAPK10 gene.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.