Reuner K H, Wiederhold M, Schlegel K, Just I, Katz N
Institut für Klinische Chemie und Pathobiochemie, Universität Giessen, Germany.
Eur J Clin Chem Clin Biochem. 1995 Sep;33(9):569-74. doi: 10.1515/cclm.1995.33.9.569.
Hypotonic treatment of cultured rat hepatocytes significantly decreased the monomeric G-actin level by 18% after 120 min while the level of filamentous F-actin remained essentially unchanged. Simultaneously the level of cellular actin mRNA was increased by 53%. Incubation of hepatocytes for 120 min with the F-actin stabilizing toxin phalloidin from Amanita phalloides led to a decrease of G-actin by 70% and an increase of F-actin by 55%. Although the toxin dependent decrease of G-actin was much more pronounced than the decrease after hypotonic treatment, the increase of actin mRNA was similar under both conditions. Simultaneous treatment with hypotonic medium did not result in a further decrease of the G-actin level. On the other hand, the G-actin elevating C2 toxin from Clostridium botulinum completely blocked the effects of osmotic stress on G-actin and actin-mRNA content. The results demonstrate that already an essentially physiological decrease of G-actin without alterations of F-actin results in a substantial enhancement of the actin mRNA level, indicating the physiological significance of this autoregulation.
对培养的大鼠肝细胞进行低渗处理120分钟后，单体G-肌动蛋白水平显著降低了18%，而丝状F-肌动蛋白水平基本保持不变。同时，细胞肌动蛋白mRNA水平增加了53%。用来自毒蝇伞的F-肌动蛋白稳定毒素鬼笔环肽孵育肝细胞120分钟，导致G-肌动蛋白减少70%，F-肌动蛋白增加55%。尽管毒素依赖性的G-肌动蛋白减少比低渗处理后的减少更为明显，但在两种情况下肌动蛋白mRNA的增加是相似的。用低渗培养基同时处理并没有导致G-肌动蛋白水平进一步降低。另一方面，来自肉毒杆菌的G-肌动蛋白升高毒素C2完全阻断了渗透应激对G-肌动蛋白和肌动蛋白mRNA含量的影响。结果表明，即使在F-肌动蛋白无变化的情况下，G-肌动蛋白出现本质上的生理性减少也会导致肌动蛋白mRNA水平大幅提高，这表明这种自动调节具有生理意义。
