JNK1 Recombinant Protein

Function: Serine/threonine-protein kinase involved in various processes such as cell proliferation, differentiation, migration, transformation and programmed cell death. Extracellular stimuli such as proinflammatory cytokines or physical stress stimulate the stress-activated protein kinase/c-Jun N-terminal kinase (SAP/JNK) signaling pathway. In this cascade, two dual specificity kinases MAP2K4/MKK4 and MAP2K7/MKK7 phosphorylate and activate MAPK8/JNK1. In turn, MAPK8/JNK1 phosphorylates a number of transcription factors, primarily components of AP-1 such as JUN, JDP2 and ATF2 and thus regulates AP-1 transcriptional activity. Phosphorylates the replication licensing factor CDT1, inhibiting the interaction between CDT1 and the histone H4 acetylase HBO1 to replication origins. Loss of this interaction abrogates the acetylation required for replication initiation. Promotes stressed cell apoptosis by phosphorylating key regulatory factors including p53/TP53 and Yes-associates protein YAP1. In T-cells, MAPK8 and MAPK9 are required for polarized differentiation of T-helper cells into Th1 cells. Contributes to the survival of erythroid cells by phosphorylating the antagonist of cell death BAD upon EPO stimulation. Mediates starvation-induced BCL2 phosphorylation, BCL2 dissociation from BECN1, and thus activation of autophagy. Phosphorylates STMN2 and hence regulates microtubule dynamics, controlling neurite elongation in cortical neurons. In the developing brain, through its cytoplasmic activity on STMN2, negatively regulates the rate of exit from multipolar stage and of radial migration from the ventricular zone

By similarity. Phosphorylates several other substrates including heat shock factor protein 4 (HSF4), the deacetylase SIRT1, ELK1, or the E3 ligase ITCH. Ref.2 Ref.5 Ref.6 Ref.13 Ref.14

Catalytic activity: ATP + a protein = ADP + a phosphoprotein.

Cofactor: Magnesium. Ref.4

Enzyme regulation: Inhibited by SERPINB3

By similarity. Activated by threonine and tyrosine phosphorylation by either of two dual specificity kinases, MAP2K4 and MAP2K7. MAP2K4 shows a strong preference for Tyr-185 while MAP2K7 phosphorylates Tyr-183 preferentially. Inhibited by dual specificity phosphatases, such as DUSP1. Ref.5

Subunit structure: Binds to at least four scaffolding proteins, MAPK8IP1/JIP-1, MAPK8IP2/JIP-2, MAPK8IP3/JIP-3/JSAP1 and SPAG9/MAPK8IP4/JIP-4. These proteins also bind other components of the JNK signaling pathway. Forms a complex with MAPK8IP1 and ARHGEF28. Interacts with TP53 and WWOX. Interacts with JAMP. Interacts with NFATC4. Interacts with MECOM; regulates JNK signaling. Interacts with PIN1; this interaction mediates MAPK8 conformational changes leading to the binding of MAPK8 to its substrates

By similarity. Interacts (phosphorylated form) with NFE2; the interaction phosphorylates NFE2 in undifferentiated cells. Ref.1 Ref.7 Ref.8 Ref.9 Ref.10 Ref.13

Subcellular location: Cytoplasm. Nucleus

By similarity Ref.12.

Developmental stage: At 15.5 dpc, mid to low expression throughout the midbrain, with more prominent levels in the telencephalon, especially in the intermediate zone, the midbrain roof, the olfactory epithelium, the inferior colliculus, and the medulla oblongata. telencephalon revealed concentrated (at protein level). Ref.12

Induction: In T-cells, following T-cell receptor (TCR) activation. Levels peak 48 hours after TCR and CD-28 costimulation. Ref.3 Ref.4 Ref.5

Domain: The TXY motif contains the threonine and tyrosine residues whose phosphorylation activates the MAP kinases.

Post-translational modification: Phosphorylated by TAOK2

By similarity. Dually phosphorylated on Thr-183 and Tyr-185 by MAP2K7 and MAP2K4, which activates the enzyme. Ref.7

Disruption phenotype: At 14.5 dpc, brain intermediate zone and cortical plate are significantly thicker in mutant mice compared to wild type. The number of neuronal cells is increased in the cortical plate and intermediate zone. Cell cycle exit is decreased by 13% in the ventricular and subventricular zones. In 17.5 dpc brains, the ventricular zone was thinner in mutant mice compared to wild type animals, consistent with the increased number of neurons in the cortical plate. TUBB3 is consistently more diffuse and less structured in mutant telencephalon than in wild type. Ref.14

Sequence similarities: Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. MAP kinase subfamily.Contains 1 protein kinase domain.