Gronostajski R M, Pardee A B
J Cell Physiol. 1984 Apr;119(1):127-32. doi: 10.1002/jcp.1041190120.
To study the relation of overall rates of protein degradation in the control of cell growth, we determined if transformation of fibroblasts to tumorigenicity affected their rates of degradation of short- and long-lived proteins. Rates of protein degradation were measured in nontumorigenic mouse Balb/c 3T3 fibroblasts, and in tumorigenic 3T3 cells transformed by different agents. Growing 3T3 cells, and cells transformed with Moloney sarcoma virus (MA-3T3) or Rous sarcoma virus (RS-3T3), degraded short- and long-lived proteins at similar rates. Simian virus 40 (SV-3T3)- and benzo(a)pyrene (BP-3T3)-transformed cells had slightly lower rates of degradation of both short- and long-lived proteins. Reducing the serum concentration in the culture medium from 10% to 0.5%, immediately caused about a twofold increase in the rate of degradation of long-lived proteins in 3T3 cells. Transformed lines increased their rates of degradation of long-lived proteins only by different amounts upon serum deprivation, but none of them to the same extent as did 3T3. Greater differences in the degradation rates of proteins were seen among the transformed cells than between 3T3 cells and some transformed cells. Thus, there was no consistent change in any rate of protein degradation in 3T3 cells due to transformation to tumorigenicity.
为了研究蛋白质降解总速率在细胞生长控制中的关系，我们确定了成纤维细胞向致瘤性的转化是否会影响其短寿命和长寿命蛋白质的降解速率。在非致瘤性小鼠Balb/c 3T3成纤维细胞以及由不同试剂转化的致瘤性3T3细胞中测量蛋白质降解速率。生长中的3T3细胞，以及用莫洛尼肉瘤病毒（MA-3T3）或劳氏肉瘤病毒（RS-3T3）转化的细胞，以相似的速率降解短寿命和长寿命蛋白质。猿猴病毒40（SV-3T3）和苯并(a)芘（BP-3T3）转化的细胞中，短寿命和长寿命蛋白质的降解速率略低。将培养基中的血清浓度从10%降至0.5%，会立即导致3T3细胞中长寿命蛋白质的降解速率增加约两倍。血清剥夺后，转化细胞系仅以不同幅度提高其长寿命蛋白质的降解速率，但没有一个能达到3T3细胞提高的程度。与3T3细胞和一些转化细胞之间相比，转化细胞之间蛋白质降解速率的差异更大。因此，3T3细胞向致瘤性转化后蛋白质降解速率没有一致变化。
