Lubs-Haukeness J, Klein C
J Biol Chem. 1982 Oct 25;257(20):12204-8.
Stimulation of Dictyostelium discoideum amoebae with cAMP was found to induce the specific phosphorylation of a 47,000 molecular weight protein (pP47). This cellular response to cAMP was developmentally regulated. It was first detected in 3 1/2-h starved cells and appeared to persist throughout the aggregation phase of the cells' life cycle. pP47 phosphorylation was specifically induced by cAMP in that amoebae did not respond to stimulation with 5'-AMP, folic acid, Ca2+, and/or the Ca2+ ionophore A23187. cGMP could elicit pP47 phosphorylation but only at high concentrations. Phosphorylation of pP47 in response to cAMP occurred rapidly (within 5 s). The length of time for which it remained phosphorylated depended upon the concentration of the stimulus. With 10(-6) M cAMP, pP47 was phosphorylated for less than 4 min. If amoebae were stimulated with 10(-4) M cAMP, over 30 min were necessary before pP47 was dephosphorylated. Once dephosphorylated, pP47 could again be phosphorylated upon reapplication of the cAMP stimulus.
研究发现，用环磷酸腺苷（cAMP）刺激盘基网柄菌变形虫可诱导一种分子量为47,000的蛋白质（pP47）发生特异性磷酸化。这种对cAMP的细胞反应受发育调控。它最早在饥饿3.5小时的细胞中被检测到，并且似乎在细胞生命周期的聚集阶段持续存在。pP47磷酸化是由cAMP特异性诱导的，因为变形虫对5'-AMP、叶酸、Ca2+和/或Ca2+离子载体A23187的刺激没有反应。环磷酸鸟苷（cGMP）可以引发pP47磷酸化，但仅在高浓度时。响应cAMP的pP47磷酸化迅速发生（在5秒内）。其保持磷酸化的时间长度取决于刺激的浓度。用10^(-6) M cAMP时，pP47磷酸化不到4分钟。如果用10^(-4) M cAMP刺激变形虫，则在pP47去磷酸化之前需要超过30分钟。一旦去磷酸化，重新施加cAMP刺激时pP47可再次被磷酸化。
