The Dictyostelium MAPK ERK1 is phosphorylated in a secondary response to early developmental signaling.
The Dictyostelium MAPK ERK1 is phosphorylated in a secondary response to early developmental signaling.
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盘基网柄菌 MAPK ERK1 在对早期发育信号的二次反应中被磷酸化。
DOI：
10.1016/j.cellsig.2014.10.009
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发表时间：
2015
影响因子：
4.8
通讯作者：
Hadwiger,JeffreyA
中科院分区：
文献类型：
--
作者：
Schwebs,DavidJ;Hadwiger,JeffreyA
先前的报道表明，两个丝裂原活化蛋白激酶（MAPK）在盘基网柄藻，ERK 1和ERK 2，可以直接激活响应外部cAMP，即使这些MAPK发挥不同的作用，在发育的生命周期。为了更好地表征MAPK调节，分析响应于外部信号的磷酸化MAPK的水平。只有ERK 2迅速磷酸化的化学引诱剂，cAMP和叶酸。相反，ERK 1的磷酸化作为对这些刺激的次级或间接反应而发生，并且这种磷酸化通过细胞-细胞相互作用而增强，这表明其他外部信号可以激活ERK 1。ERK 1或ERK 2的磷酸化在这些反应中不需要其他MAPK的功能。叶酸对k1 −和g α 4 −嵌合细胞群的刺激显示，ERK 1的磷酸化可以通过叶酸以外的细胞间信号介导。ERK 1功能的丧失抑制了与g α 5 −突变体相关的发育延迟和前细胞定位缺陷，表明ERK 1功能可以通过G α 5亚基介导的信号转导下调。然而，在α 5 −细胞中没有观察到ERK 1磷酸化的重大变化，表明G α 5亚基信号通路不调节ERK 1的磷酸化。这些发现表明，ERK 1的激活作为对化学引诱物的次级反应而发生，并且其他细胞-细胞信号传导机制有助于这种激活。G α 5亚基信号可以下调ERK 1的功能，促进prestalk细胞的发育，但不是通过磷酸化ERK 1的水平的重大变化。
Previous reports have suggested that the two mitogen-activated protein kinases (MAPKs) in Dictyostelium discoideum, ERK1 and ERK2, can be directly activated in response to external cAMP even though these MAPKs play different roles in the developmental life cycle. To better characterize MAPK regulation, the levels of phosphorylated MAPKs were analyzed in response to external signals. Only ERK2 was rapidly phosphorylated in response to the chemoattractants, cAMP and folate. In contrast, the phosphorylation of ERK1 occurred as a secondary or indirect response to these stimuli and this phosphorylation was enhanced by cell–cell interactions, suggesting that other external signals can activate ERK1. The phosphorylation of ERK1 or ERK2 did not require the function of the other MAPK in these responses. Folate stimulation of a chimeric population oferk1−andgα4−cells revealed that the phosphorylation of ERK1 could be mediated through an intercellular signal other than folate. Loss of ERK1 function suppressed the developmental delay and the deficiency in anterior cell localization associated withgα5−mutants suggesting that ERK1 function can be down regulated through Gα5 subunit-mediated signaling. However, no major changes in the phosphorylation of ERK1 were observed ingα5−cells suggesting that the Gα5 subunit signaling pathway does not regulate the phosphorylation of ERK1. These findings suggest that the activation of ERK1 occurs as a secondary response to chemoattractants and that other cell–cell signaling mechanisms contribute to this activation. Gα5 subunit signaling can down regulate ERK1 function to promote prestalk cell development but not through major changes to the level of phosphorylated ERK1.