PH REGULATION OF THE F-ACTIN BINDING-PROPERTIES OF DICTYOSTELIUM ELONGATION-FACTOR 1-ALPHA
PH REGULATION OF THE F-ACTIN BINDING-PROPERTIES OF DICTYOSTELIUM ELONGATION-FACTOR 1-ALPHA
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DOI：
10.1074/jbc.270.25.15222
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发表时间：
1995-06-23
影响因子：
4.8
通讯作者：
CONDEELIS, J
中科院分区：
文献类型：
--
作者：
EDMONDS, BT;MURRAY, J;CONDEELIS, J
ABP 50是一种来自网骨藻的F-肌动蛋白捆绑蛋白，也是蛋白质合成辅因子，延伸因子1 α（EF 1 α）。在网骨藻中伴随cAMP刺激的是细胞质碱化（Aestheti，R. J.，德威特河J. W.，和货车Lookeren Campagne，M. M. 04 The Dog（1987）220，366-370）和EF 1 α的重新分布（Dharmawardhane，S.，Demma，M.，杨，F.，和Condeelis，J.（1991）Cell Motil.细胞骨架20，279-288）。此外，其他人已经显示了网骨藻中细胞内pH和蛋白质合成水平之间的相关性（Aesthetic，R. J.，Durston，A. J.，和Moolenaar，W. H.（1985）Cell 43，653-657）。本研究探讨了pH值和EF 1 α的F-肌动蛋白结合特性之间的关系。我们发现，在生理范围6.2-7.8内增加pH值会导致EF 1 α介导的F-肌动蛋白成束和单丝结合的损失，同时体外游离EF 1 α的量相应增加。通过细胞分级分离和共聚焦免疫荧光显微镜也获得了类似的结果。在相同的pH范围内，F-肌动蛋白的EF 1 α结合常数（K-d）从0.2 μ M增加到> 2.2 μ M。此外，EF 1 α诱导的肌动蛋白束的形成是自由可逆的pH值的变化。因此，pH值可能是一个有效的调制器的细胞结构在Dictyosteoprotein，也可能影响mRNA的翻译速率，通过修改之间的相互作用的蛋白质合成机器和肌动蛋白的细胞骨架。
ABP50, an F-actin bundling protein from Dictyostelium, is also the protein synthesis co-factor, elongation factor 1 alpha (EF1 alpha). Concomitant with cAMP stimulation in Dictyostelium is a cytoplasmic alkalinization (Aerts, R. J., DeWit, R. J. W., and Van Lookeren Campagne, M. M. (1987) FEES Lett. 220, 366-370) and a redistribution of EF1 alpha (Dharmawardhane, S., Demma, M., Yang, F., and Condeelis, J. (1991) Cell Motil. Cytoskel. 20, 279-288). In addition, others have shown a correlation between intracellular pH and the level of protein synthesis in Dictyostelium (Aerts, R. J., Durston, A. J., and Moolenaar, W. H. (1985) Cell 43, 653-657). The present study investigates the relationship between pH and the F-actin binding properties of EF1 alpha. We found that increasing pH over the physiological range 6.2-7.8 causes a loss of EF1 alpha-mediated F-actin bundling and single filament binding, with corresponding increases in the amount of free EF1 alpha in vitro. Similar results also were obtained by cell fractionation and confocal immunofluorescence microscopy. The EF1 alpha binding constant (K-d) for F-actin is increased from 0.2 mu M to > 2.2 mu M over the same pH range. In addition, EF1 alpha-induced actin bundle formation is freely reversible by changes in pH. Thus, pH may be a potent modulator of cytoarchitecture in Dictyostelium and may also influence mRNA translation rates by modifying the interactions between the protein synthetic machinery and the actin cytoskeleton.