Premium
IκBα Associates with Nuclear Matrix in Human Neutrophils: Correlation of the Nuclear IκBα to NFκB Activation
Author(s) -
Miskolci Veronika,
Romero Carlos,
Rollins Janet,
Davidson Dennis,
Vancurova Ivana
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a224-d
Subject(s) - nuclear matrix , nf κb , lamin , p50 , cell nucleus , apoptosis , microbiology and biotechnology , immunofluorescence , iκbα , nuclear localization sequence , cytosol , nucleus , chemistry , nuclear protein , transcription factor , inflammation , biology , signal transduction , immunology , gene , biochemistry , antibody , chromatin , enzyme
Neutrophils are among the first circulating leukocytes involved in acute inflammatory processes. Transcription factor NFκB plays a key role in the inflammatory response, regulating expression of pro‐inflammatory and anti‐apoptotic genes. Recently we have shown that human neutrophils contain predominant amount of NFκB inhibitor, IκBα in the nucleus of unstimulated cells, and this increased nuclear levels of IκBα are associated with the inhibition of NFκB activity and increased apoptosis. The purpose of this study was to analyze the subnuclear localization of IκBα in human neutrophils, and to determine whether the nuclear levels of IκBα could be used as a marker of NFκB activation in the neutrophils. Immunofluorescence confocal microscopy revealed a punctuate nuclear staining of IκBα in resting neutrophils. Biochemical fractionation showed that in resting neutrophils, IκBα associates with the nuclear matrix that also contained SUMO‐1 and lamin B. In addition, the NFκB proteins p50 and p65 co‐localized with IκBα in the nuclear matrix fraction of resting neutrophils. Immunofluorescence microscopy showed that neutrophil stimulation with pro‐inflammatory signals resulted in decreased nuclear levels of IκBα, and in the NFκB activation. Together, our results show, for the first time, that IκBα localizes in the nuclear matrix of human neutrophils, and suggest that the nuclear levels of IκBα serve as a better predictor of NFκB activation in human neutrophils than the nuclear levels of p50 and p65 NFκB subunits.