Anti-MAPK8/9 Antibody Picoband® Fluoro488 Conjugated

Mitogen-activated protein kinase 8 is an enzyme that in humans is encoded by the MAPK8 gene. The protein encoded by this gene is a member of the MAP kinase family. The International Radiation Hybrid Mapping Consortium mapped the MAPK8 gene to chromosome 10. The single long open reading frame encodes a putative protein kinase with a predicted mass of 44.2 kD. This kinase play a key role in T cell proliferation, apoptosis and differentiation. The protein encoded by MAPK9 gene is also a member of the MAP kinase 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 targets specific transcription factors, and thus mediates immediate-early gene expression in response to various cell stimuli. It is most closely related to MAPK8, both of which are involved in UV radiation induced apoptosis, thought to be related to the cytochrome c-mediated cell death pathway. This gene and MAPK8 are also known as c-Jun N-terminal kinases. This kinase blocks the ubiquitination of tumor suppressor p53, and thus it increases the stability of p53 in nonstressed cells. Studies of this gene's mouse counterpart suggest a key role in T-cell differentiation. Several alternatively spliced transcript variants encoding distinct isoforms have been reported.

Mitogen-activated protein kinase 8; MAP kinase 8; MAPK 8;2.7.11.24; JNK-46; Stress-activated protein kinase 1c; SAPK1c; Stress-activated protein kinase JNK1; c-Jun N-terminal kinase 1; MAPK8; JNK1, PRKM8, SAPK1, SAPK1C; JNK2, MAPK9

Cancer, Cancer Susceptibility, Epigenetics and Nuclear Signaling, Immunology, Innate Immunity, MAPK Pathway, Oncoproteins, Oncoproteins/Suppressors, Protein Phosphorylation, Proto-Oncogenes, Ser/Thr Kinases, Serine/Threonine Kinases, Signal Transduction, TLR Signaling, Transcription

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. Phosphorylates several other substrates including heat shock factor protein 4 (HSF4), the deacetylase SIRT1, ELK1, or the E3 ligase ITCH. Phosphorylates the CLOCK-ARNTL/BMAL1 heterodimer and plays a role in the regulation of the circadian clock (PubMed:22441692) . .

1. Derijard B, Hibi M, Wu IH, Barrett T, Su B, Deng T, Karin M, Davis RJ (Apr 1994) . JNK1: a protein kinase stimulated by UV light and Ha-Ras that binds and phosphorylates the c-Jun activation domain. Cell 76 (6) : 1025–37. doi:10.1016/0092-8674 (94) 90380-8. PMID 8137421. 2. Gupta S, Barrett T, Whitmarsh AJ, Cavanagh J, Sluss HK, Derijard B, Davis RJ (Jul 1996) . Selective interaction of JNK protein kinase isoforms with transcription factors. EMBO J 15 (11) : 2760–70. PMC 450211. PMID 8654373.