| 1. |
- Babakov, V.N., et al.
(författare)
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RelA/NF-?B transcription factor associates with a-actinin-4
- 2008
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 314:5, s. 1030-1038
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Tidskriftsartikel (refereegranskat)abstract
- The NF-?B/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-?B in the cytoplasm and the transport mechanism to the nucleus. We found that NF-?B is associated with the actin-binding protein a-actinin-4. NF-?B and a-actinin-4 co-localized along actin stress fibers and in membrane lamellae in A431 cells. After a 30-min stimulation with EGF or TNF-a, a-actinin-4 and p65 were found in the nucleus. Disruption of cytoskeleton by cytochalasin D prior to treatment with TNF-a led to increase of p65 nuclear translocation. Antibodies to p65 subunit of NF-?B co-immunoprecipitated a-actinin-4 from A431 cell lysates and nuclear extracts, but a-actinin-1 and ß-actin were not found in the precipitates. Affinity chromatography experiments displayed that p65 and p50 subunits of NF-?B can bind to matrix-bound chicken gizzard a-actinin. We suggest that the a-actinin-4 is important for the NF-?B nuclear translocation and its functions inside the nucleus. © 2007 Elsevier Inc. All rights reserved.
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| 2. |
- Khotin, M.G., et al.
(författare)
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Analysis of nuclear protein complexes comprising a-actinin-4 by 2D-electrophoresis and mass-spectrometry
- 2009
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Ingår i: Tsitologiya. - : SP MAIK Nauka/Interperiodica. - 0041-3771. ; 51:8, s. 684-690
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Tidskriftsartikel (refereegranskat)abstract
- Actin-binding protein a-actinin-4 is a member of spectrin super family. It is located in the cytoplasm and in the nucleus. However, nuclear functions of a-actinin-4 are still not clear. In this study, we analyzed composition of nuclear protein complexes associated with a-actinin-4 in A431 cells. Using 2D electrophoresis, we have determined that about 50 different proteins may be associated with nuclear a-actinin-4. Using mass-spectrometry, we analyzed major proteins of these complexes. ß-Actin, a- and ß-tubulins, ribonucleoprotein A2/B1, which regulates splicing and is associated with ß-actin, peroxiredoxin-1, which is involved in oxidative stress, and glycolytic enzyme D-3-phosphoglycerate dehydrogenase were identified by MALDI-TOF. Detection of these proteins in nuclear complexes with a-actinin-4 may suggest that a-actinin-4 is involved in transcription and splicing. Presence of a-actin in the investigated complexes was confirmed by tandem mass-spectrometry (MALDITOF-TOF). Immunoprecipitation of nuclear proteins with antibodies against a-tubulin confirmed association of a-actinin-4 with a-tubulin in the protein complex. Nuclear a-actinin-4 constitutes of 105 KDa fullsize isoform and two truncated isoforms of 65 and 75 kDa, whereas only the truncated isoform have been found in nuclear complexes with a-tubulin. These data suggest that a-actinin-4 is associated with a number of different nuclear protein complexes which may carry out different functions in the cell nucleus.
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