title: EGF-induced dynamics of NF-κB and F-actin in A431 cells spread on fibronectin.
abstract: To evaluate the role of actin cytoskeleton in the regulation of NF-κB transcription factor, we analyzed its involvement in the intracellular transport and nuclear translocation of the NF-κB RelA/p65 subunit in A431 epithelial cells stimulated with fibronectin and EGF. Live cell imaging and confocal microscopy showed that EGF activated the movement of RelA/p65 in the cytoplasm. Upon cell adhesion to fibronectin, RelA/p65 concentrated onto stress fibers, and EGF stimulated its subsequent allocation to membrane ruffles, newly organized stress fibers, and discrete cytoplasmic actin-rich patches. These patches also contained α-actinin-1 and α-actinin-4, vinculin, paxillin, α-tubulin, and PI3-kinase. Cytochalasin D treatment resulted in RelA/p65 redistribution to actin-containing aggregates, with the number of cells with RelA/p65-containing clusters in the cytoplasm increasing under the effect of EGF. Furthermore, EGF proved to induce RelA/p65 accumulation in the nucleus after cell pretreatment with actin-stabilizing and actin-destabilizing agents, which was accompanied by changes in its DNA-binding activity after either EGF stimulation or cytochalasin D treatment. Thus, EGF treatment of A431 cells results in simultaneous nuclear RelA/p65 translocation and cytoplasmic redistribution, with part of RelA/p65 pool forming a very tight association with actin-rich structures. Apparently, nuclear transport is independent on drug stabilization or destabilization of the actin.
authors.affiliation: Department of Cell Cultures, Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Ave., St. Petersburg, 194064, Russia.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Bolshakova
authors.forename: Karl-Eric
authors.initials: KE
authors.lastname: Magnusson
authors.forename: George
authors.initials: G
authors.lastname: Pinaev
authors.forename: Olga
authors.initials: O
authors.lastname: Petukhova
mesh_terms: D000199:Actins / Q000187:drug effects / Q000378:metabolism*; D002460:Cell Line; D045744:Cell Line, Tumor; D015638:Cytochalasin D / Q000494:pharmacology; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D016328:NF-kappa B / Q000096:biosynthesis; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D051996:Transcription Factor RelA / Q000187:drug effects / Q000378:metabolism*; D014178:Translocation, Genetic / Q000187:drug effects
chemical_list: D000199:Actins; D005353:Fibronectins; D016328:NF-kappa B; D019384:Nucleic Acid Synthesis Inhibitors; C498143:RELA protein, human; D051996:Transcription Factor RelA; D015638:Cytochalasin D; D004815:Epidermal Growth Factor