Anti-PKR/EIF2AK2 Antibody Picoband®, APC Conjugate

EIF2AK2 (Eukaryotic Translation Initiation Factor 2-Alpha Kinase 2), also called PKR, is an enzyme that in humans is encoded by the EIF2AK2 gene. Activation of EIF2AK2 allows the kinase to phosphorylate its natural substrate, the alpha subunit of eukaryotic protein synthesis initiation factor-2, leading to the inhibition of protein synthesis (summary by Kuhen et al., 1996). By FISH analysis, Squire et al. (1993) assigned the EIF2AK2 gene to the boundary between chromosome 2p22-p21. Ben-Asouli et al. (2002) showed that human gamma-interferon mRNA uses local activation of PKR in the cell to control its own translation yield. IFNG mRNA was found to activate PKR through a pseudoknot in its 5-prime untranslated region. Taylor et al. (1999) studied the mechanism underlying the resistance of hepatitis C virus (HCV) to interferon. They demonstrated that the HCV envelope protein E2 contains a sequence identical with phosphorylation sites of the interferon-inducible protein kinase PKR and the translation initiation factor EIF2-alpha, a target of PKR. E2 inhibited the kinase activity of PKR and blocked its inhibitory effect on protein synthesis and cell growth.

Interferon-induced, double-stranded RNA-activated protein kinase;2.7.11.1;Eukaryotic translation initiation factor 2-alpha kinase 2;eIF-2A protein kinase 2;Interferon-inducible RNA-dependent protein kinase;P1/eIF-2A protein kinase;Protein kinase RNA-activated;PKR;Protein kinase R ;Tyrosine-protein kinase EIF2AK2;2.7.10.2;p68 kinase;EIF2AK2;PKR, PRKR;

Highly expressed in thymus, spleen and bone marrow compared to non-hematopoietic tissues such as small intestine, liver, or kidney tissues. Colocalizes with GSK3B and TAU in the Alzheimer disease (AD) brain. Elevated levels seen in breast and colon carcinomas,and which correlates with tumor progression and invasiveness or risk of progression. .

IFN-induced dsRNA-dependent serine/threonine-protein kinase which plays a key role in the innate immune response to viral infection and is also involved in the regulation of signal transduction, apoptosis, cell proliferation and differentiation. Exerts its antiviral activity on a wide range of DNA and RNA viruses including hepatitis C virus (HCV), hepatitis B virus (HBV), measles virus (MV) and herpes simplex virus 1 (HHV-1). Inhibits viral replication via phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (EIF2S1), this phosphorylation impairs the recycling of EIF2S1 between successive rounds of initiation leading to inhibition of translation which eventually results in shutdown of cellular and viral protein synthesis. Also phosphorylates other substrates including p53/TP53, PPP2R5A, DHX9, ILF3, IRS1 and the HHV-1 viral protein US11. In addition to serine/threonine-protein kinase activity, also has tyrosine-protein kinase activity and phosphorylates CDK1 at 'Tyr-4' upon DNA damage, facilitating its ubiquitination and proteosomal degradation. Either as an adapter protein and/or via its kinase activity, can regulate various signaling pathways (p38 MAP kinase, NF-kappa-B and insulin signaling pathways) and transcription factors (JUN, STAT1, STAT3, IRF1, ATF3) involved in the expression of genes encoding proinflammatory cytokines and IFNs. Activates the NF-kappa-B pathway via interaction with IKBKB and TRAF family of proteins and activates the p38 MAP kinase pathway via interaction with MAP2K6. Can act as both a positive and negative regulator of the insulin signaling pathway (ISP). Negatively regulates ISP by inducing the inhibitory phosphorylation of insulin receptor substrate 1 (IRS1) at 'Ser- 312' and positively regulates ISP via phosphorylation of PPP2R5A which activates FOXO1, which in turn up-regulates the expression of insulin receptor substrate 2 (IRS2). Can regulate NLRP3 inflammasome assembly and the activation of NLRP3, NLRP1, AIM2 and NLRC4 inflammasomes. Can trigger apoptosis via FADD-mediated activation of CASP8. Plays a role in the regulation of the cytoskeleton by binding to gelsolin (GSN), sequestering the protein in an inactive conformation away from actin. .

1. Ben-Asouli, Y., Banai, Y., Pel-Or, Y., Shir, A., Kaempfer, R. Human interferon-gamma mRNA autoregulates its translation through a pseudoknot that activates the interferon-inducible protein kinase PKR. Cell 108: 221-232, 2002. 2. Kuhen, K. L., Shen, X., Carlisle, E. R., Richardson, A.L., Weier, H.-U. G., Tanaka, H., Samuel, C. E. Structural organization of the human gene (PKR) encoding an interferon-inducible RNA-dependent protein kinase (PKR) and differences from its mouse homolog. Genomics 36: 197-201, 1996. 3. Squire, J., Meurs, E. F., Chong, K. L., McMillan, N. A. J., Hovanessian, A. G., Williams, B. R. G. Localization of the human interferon-induced, ds-RNA activated p68 kinase gene (PRKR) to chromosome 2p21-p22. Genomics 16: 768-770, 1993. 4. Taylor, D. R., Shi, S. T., Romano, P. R., Barber, G. N., Lal, M. M. C. Inhibition of the interferon-inducible protein kinase PKR by HCV E2 protein. Science 285: 107-110, 1999.

Store at -20℃ for one year from date of receipt. After reconstitution, at 4℃ for one month. It can also be aliquotted and stored frozen at -20℃ for six months. Avoid repeated freeze-thaw cycles.

Cytoplasm. Nucleus. Cytoplasm, perinuclear region. Nuclear localization is elevated in acute leukemia, myelodysplastic syndrome (MDS), melanoma, breast, colon, prostate and lung cancer patient samples or cell lines as well as neurocytes from advanced Creutzfeldt-Jakob disease patients.