Over the next few years, both the recently identified lymphocyte lineages as well as the application of deep sequencing approaches will provide insight into the link between antigen specificity and phenotype
– and into how Th cells choose the appropriate phenotype to regulate adaptive immunity. HJvdH, AA and RdB wrote the manuscript. “
“The inhibitor this website of κB kinase ε (IKKε) is pivotal for an efficient innate immune response to viral infections and has been recognized as breast cancer oncogene. The antiviral function of IKKε involves activation of the transcription factors IFN regulatory factor 3 (IRF3) and NF-κB, thus inducing the expression of type I IFN. Here, we have identified two novel splice variants of human IKKε, designated IKKε-sv1 and IKKε-sv2, respectively. Interestingly,
RT-PCR revealed quantitatively different isoform expression in PBMC from different individuals. Moreover, we found cell type- and stimulus-specific protein expression of the various splice variants. Overexpression of full-length wt IKKε (IKKε-wt) leads learn more to the activation of NF-κB- as well as IRF3-driven luciferase reporter genes. Although none of the splice variants activates IRF3, IKKε-sv1 still activates NF-κB, whereas IKKε-sv2 is also defective in NF-κB activation. Both splice variants form dimers with IKKε-wt and inhibit IKKε-wt-induced IRF3 signaling including the antiviral activity in a dominant-negative manner. The lack of IRF3 activation is
likely caused by the failure of the splice variants to Farnesyltransferase interact with the adapter proteins TANK, NAP1, and/or SINTBAD. Taken together, our data suggest alternative splicing as a novel regulatory mechanism suitable to shift the balance between different functions of IKKε. Viral infections are recognized by the innate immune system, which is essential for the subsequent initiation of adaptive immunity. Invading viruses are sensed by pattern-recognition receptors (PRR) recognizing pathogen-associated molecular patterns such as single- or double-stranded RNA. These PRR comprise TLR with endosomal/lysosomal localization like TLR3 and cytoplasmic receptors such as the retinoic acid-inducible protein I and melanoma differentiation-associated gene 5. Activation of these PRR engages intracellular signaling cascades leading to the secretion of type I IFN, which are important anti-viral cytokines ultimately facilitating viral clearance 1, 2. The signal transduction pathways leading to type I IFN expression involve activation of the serine/threonine kinases TANK-binding kinase 1 (TBK-1), also known as NF-κB activating kinase NAK 3, and inhibitor of κB kinase ε (IKKε), also known as IKKi 4.