Steinberg R A, Agard D A
J Biol Chem. 1981 Nov 10;256(21):10731-4.
Turnover of regulatory subunit (R) of type I cAMP-dependent protein kinase in intact S49 mouse lymphoma cells was studied using two-dimensional gel electrophoresis to analyze [35S]methionine label in R during label-chase experiments. R decays exponentially with a half-life of about 8.4 h in drug-free, wild type cells. In mutant cells lacking functional kinase catalytic subunit, R is about 10 times more labile than in wild type cells. 8-bromo-cAMP, isoproterenol, and cholera toxin destabilize R in wild type cells to an extent comparable to the "kinase-negative" mutation. In contrast, dibutyryl-cAMP stabilizes R in both wild type and kinase-negative cells. Sodium butyrate has no significant effect on R stability. These results are discussed in terms of R structure and the regulation of R expression.
利用二维凝胶电泳分析[35S]甲硫氨酸标记在追踪实验期间I型环磷酸腺苷依赖性蛋白激酶调节亚基（R）中的情况，以此研究完整S49小鼠淋巴瘤细胞中该调节亚基的周转率。在无药物的野生型细胞中，R呈指数衰减，半衰期约为8.4小时。在缺乏功能性激酶催化亚基的突变细胞中，R的稳定性比野生型细胞中约低10倍。8-溴环磷酸腺苷、异丙肾上腺素和霍乱毒素使野生型细胞中的R不稳定，其程度与“激酶阴性”突变相当。相比之下，二丁酰环磷酸腺苷使野生型和激酶阴性细胞中的R均趋于稳定。丁酸钠对R的稳定性无显著影响。本文从R结构和R表达调控方面对这些结果进行了讨论。
