RelA/NF-kappaB transcription factor associates with alpha-actinin-4.
The NF-kappaB/RelA family of transcription factors regulates inducible transcription of a large number of genes in response to diverse stimuli. Little is known, however, about the location of NF-kappaB in the cytoplasm and the transport mechanism to the nucleus. We found that NF-kappaB is associated with the actin-binding protein alpha-actinin-4. NF-kappaB and alpha-actinin-4 co-localized along actin stress fibers and in membrane lamellae in A431 cells. After a 30-min stimulation with EGF or TNF-alpha, alpha-actinin-4 and p65 were found in the nucleus. Disruption of cytoskeleton by cytochalasin D prior to treatment with TNF-alpha led to increase of p65 nuclear translocation. Antibodies to p65 subunit of NF-kappaB co-immunoprecipitated alpha-actinin-4 from A431 cell lysates and nuclear extracts, but alpha-actinin-1 and beta-actin were not found in the precipitates. Affinity chromatography experiments displayed that p65 and p50 subunits of NF-kappaB can bind to matrix-bound chicken gizzard alpha-actinin. We suggest that the alpha-actinin-4 is important for the NF-kappaB nuclear translocation and its functions inside the nucleus.
Babakov
Vladimir N
VN
Department of Cell Cultures, Institute of Cytology, St Petersburg, Russian Federation. vbabakov@gmail.com
Petukhova
Olga A
OA
Turoverova
Lidia V
LV
Kropacheva
Irina V
IV
Tentler
Dmitri G
DG
Bolshakova
Anastasia V
AV
Podolskaya
Ekaterina P
EP
Magnusson
Karl-Eric
KE
Pinaev
George P
GP
D000185:Actinin / Q000378:metabolism*; D021581:Active Transport, Cell Nucleus; D000818:Animals; D045744:Cell Line, Tumor; D002645:Chickens; D003593:Cytoplasm / Q000737:chemistry; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism*; D052002:NF-kappa B p50 Subunit / Q000378:metabolism*; D011485:Protein Binding; D022502:Stress Fibers; D051996:Transcription Factor RelA / Q000378:metabolism*
C111453:ACTN4 protein, human; D008840:Microfilament Proteins; D052002:NF-kappa B p50 Subunit; D051996:Transcription Factor RelA; D000185:Actinin