CHEMOATTRACTANT-ELICITED INCREASES IN MYOSIN PHOSPHORYLATION IN DICTYOSTELIUM
CHEMOATTRACTANT-ELICITED INCREASES IN MYOSIN PHOSPHORYLATION IN DICTYOSTELIUM
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DOI：
10.1016/0092-8674(85)90036-4
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发表时间：
1985-01-01
期刊：
影响因子：
64.5
通讯作者：
DEVREOTES, PN
中科院分区：
文献类型：
--
作者：
BERLOT, CH;SPUDICH, JA;DEVREOTES, PN
用[32P]正磷酸盐标记的具有化学活性的Dictyostelialamebas的环状AMP刺激瞬间增加了肌球蛋白重链和18000道尔顿轻链的磷酸化。紧接在增加之前，重链磷酸化一过性降低。当cAMP诱导的腺苷环化酶的激活被咖啡因预处理的阿米巴阻断时，这些磷酸化变化也会发生。这些磷酸化反应的时间进程与暴露于cAMP浓度短暂增加的阿米巴引起的形状变化有关。磷酸化反应的剂量依赖关系与先前确定的趋化作用相同。磷酸化反应表现出与形状改变反应和趋化反应相同的适应特性。通过用cAMP刺激未标记的阿米巴，然后将细胞裂解成含有γ-[~(32)P]ATP的反应混合物，可以在体外观察到肌球蛋白重链磷酸化的速度增加。
Cyclic AMP stimulation of chemotactically competent Dictyostelium amebas labeled with [32P]orthophosphate transiently increases phosphorylation in the heavy chain and the 18,000 dalton light chain of myosin. Immediately before the increase, heavy chain phosphorylation transiently decreases. These phosphorylation changes also occur when cAMP-induced activation of adenylate cyclase is blocked by pretreatment of amebas with cafffeine. The time course of these phosphorylation responses correlates with the shape changes induced in amebas exposed to a temporal increase in cAMP concentration. The dose dependence of the phosphorylation responses is the same as that previously determined for chemotaxis. The phosphorylation responses exhibit adaptation properties in common with those of the shape change response and chemotaxis. Increases in the rate of myosin heavy chain phosphorylation can be observed in vitro by stimulating unlabeled amebas with cAMP and then lysing the cells into a .gamma.-[32P]ATP-containing reaction mixture.