Bolshakova Anastasia, Petukhova Olga, Turoverova Lidia, Tentler Dmitri, Babakov Vladimir, Magnusson Karl-Eric, Pinaev George
Department of Cell Cultures, Institute of Cytology, Tikhoretsky Avenue 4, St. Petersburg 194064, Russian Federation.
Cell Biol Int. 2007 Apr;31(4):360-5. doi: 10.1016/j.cellbi.2007.01.021. Epub 2007 Jan 21.
Alpha-actinins are actin-binding proteins of non-muscle cells, which can participate in the regulation of transcription factor activity. We describe the distribution of alpha-actinin-1 and -4 depending on different actin cytoskeleton formed as a result of cell adhesion to extracellular matrix proteins, such as fibronectin and laminin 2/4. Immunofluorescent studies show a difference in the distribution of alpha-actinin and -4. Both isoforms localise along stress-fibres, but alpha-actinin-1 localises in the perinuclear region more abundantly than alpha-actinin-4. Western blot analysis demonstrated existence of truncated forms of both isoforms. Truncated alpha-actinin-1 appears in cells spread on fibronectin or laminin. Cell spreading also correlated with more tight association of alpha-actinin-4 with chromatin. Basing on our previous finding of an interaction of alpha-actinin-4 with p65 subunit of the NF-kappaB, we checked the possible influence of immobilised ligands on its redistribution in nuclear complexes containing p65. alpha-Actinin-4 seems to be present in some but not all nuclear complexes containing p65. Immobilised ligands may affect the interaction of alpha-actinin-4/p65 complexes with chromatin. The data suggest that adhesion to extra-cellular matrix may interfere in cellular reactions mediated by alpha-actinin-1 and -4.
α-辅肌动蛋白是非肌肉细胞中的肌动蛋白结合蛋白，可参与转录因子活性的调节。我们描述了α-辅肌动蛋白-1和-4的分布情况，该分布取决于细胞与细胞外基质蛋白（如纤连蛋白和层粘连蛋白2/4）粘附所形成的不同肌动蛋白细胞骨架。免疫荧光研究显示了α-辅肌动蛋白-1和-4在分布上的差异。两种同工型均沿应力纤维定位，但α-辅肌动蛋白-1在核周区域的定位比α-辅肌动蛋白-4更丰富。蛋白质印迹分析表明两种同工型均存在截短形式。截短的α-辅肌动蛋白-1出现在铺展在纤连蛋白或层粘连蛋白上的细胞中。细胞铺展还与α-辅肌动蛋白-4与染色质的更紧密结合相关。基于我们之前发现的α-辅肌动蛋白-4与NF-κB的p65亚基相互作用，我们检查了固定化配体对其在含有p65的核复合物中重新分布的可能影响。α-辅肌动蛋白-4似乎存在于一些但不是所有含有p65的核复合物中。固定化配体可能会影响α-辅肌动蛋白-4/p65复合物与染色质的相互作用。数据表明，与细胞外基质的粘附可能会干扰由α-辅肌动蛋白-1和-4介导的细胞反应。
