Anti-IKK alpha polyclonal antibody

The activity of the NF-kappa B family of transcription factors is regulated principally by phosphorylation and subsequent degradation of their inhibitory I kappa B subunits. Site-specific serine phosphorylation of I kappa Bs by two I kappa B kinases (IKK alpha [also known as CHUK] and IKK beta) targets them for proteolysis. IKK alpha and -beta have a unique structure, with an amino-terminal serine-threonine kinase catalytic domain and carboxy-proximal helix-loop-helix (HLH) and leucine zipper-like (LZip) amphipathic alpha-helical domains. Here, we describe the properties of two novel cellular isoforms of IKK alpha: IKK alpha-Delta H and IKK alpha-Delta LH. IKK alpha-Delta H and IKK alpha-Delta LH are differentially spliced isoforms of the IKK alpha mRNA lacking its HLH domain and both its LZip and HLH domains, respectively. IKK alpha is the major RNA species in most murine cells and tissues, except for activated T lymphocytes and the brain, where the alternatively spliced isoforms predominate. Remarkably, IKK alpha-Delta H and IKK alpha-Delta LH, like IKK alpha, respond to tumor necrosis factor alpha stimulation to potentiate NF-kappa B activation in HEK293 cells. A mutant, catalytically inactive form of IKK alpha blocked IKK alpha-, IKK alpha-Delta H-, and IKK alpha-Delta LH-mediated NF-kappa B activation. Akin to IKK alpha, its carboxy-terminally truncated isoforms associated with the upstream activator NIK (NF-kappa B-inducing kinase). In contrast to IKK alpha, IKK alpha-Delta LH failed to associate with either itself, IKK alpha, IKK beta, or NEMO-IKK gamma-IKKAP1, while IKK alpha-Delta H complexed with IKK beta and IKK alpha but not with NEMO. Interestingly, each IKK alpha isoform rescued HEK293 cells from the inhibitory effects of a dominant-negative NEMO mutant, while IKK alpha could not. IKK alpha-Delta Cm, a recombinant mutant of IKK alpha structurally akin to IKK alpha-Delta LH, was equally functional in these assays, but in sharp contrast, IKK beta-Delta Cm, a structurally analogous mutant of IKK beta, was inactive. Our results demonstrate that the functional roles of seemingly analogous domains in IKK alpha and IKK beta need not be equivalent and can also exhibit different contextual dependencies. The existence of cytokine-inducible IKK alpha-Delta H and IKK alpha-Delta LH isoforms illustrates potential modes of NF-kappa B activation, which are not subject to the same in vivo regulatory constraints as either TKK alpha or IKK beta.

We found that regular use of aspirin may reduce the risk of Hodgkin lymphoma (HL), a common cancer of adolescents and young adults in the United States. To explore possible biological mechanisms underlying this association, we investigated whether polymorphic variation in genes involved in nuclear factor-kappa B (NF-kappa B) activation and inhibition, other inflammatory pathways, and aspirin metabolism influences HL risk. Twenty single nucleotide polymorphisms (SNP) in seven genes were genotyped in DNA from 473 classical HL cases and 373 controls enrolled between 1997 and 2000 in a population-based case-control study in the Boston, Massachusetts, metropolitan area and the state of Connecticut. We selected target genes and SNPs primarily using a candidate-SNP approach and estimated haplotypes using the expectation-maximization algorithm. We used multivariable logistic regression to estimate odds ratios (OR) for associations with HL risk. HL risk was significantly associated with rs1585215 in NFKB1 (AG versus AA: OR, 2.1; 95% confidence interval, 1.5-2.9; GG versus AA: OR, 3.5; 95% confidence interval, 2.2-5.7, P(trend) 1.7 X 10(-8)) and with NFKB1 haplotypes (P(global) = 6.0 X 10(-21)). Similar associations were apparent across categories of age, sex, tumor EBV status, tumor histology, and regular aspirin use, although statistical power was limited for stratified analyses. Nominally significant associations with HL risk were detected for SNPs in NFKBIA and CYP2C9. HL risk was not associated with SNPs in IKKA/CHUK, PTGS2/COX2, UDP1A6, or LTC4S. In conclusion, genetic variation in the NF-kappa B pathway seems to influence risk of HL. Pooled studies are needed to detect any heterogeneity in the association with NF-kappa B across HL subgroups, including aspirin users and nonusers. (Cancer Epidemiol Biomarkers Prev 2009;18(3):976-86)