Knetsch M L, Epskamp S J, Schenk P W, Wang Y, Segall J E, Snaar-Jagalska B E
Cell Biology Section, IMP, University of Leiden, The Netherlands.
EMBO J. 1996 Jul 1;15(13):3361-8.
Dictyostelium discoideum expresses two Extracellular signal Regulated Kinases, ERK1 and ERK2, which are involved in growth, multicellular development and regulation of adenylyl cyclase. Binding of extracellular cAMP to cAMP receptor 1, a G-protein coupled cell surface receptor, transiently stimulates phosphorylation, activation and nuclear translocation of ERK2. Activation of ERK2 by cAMP is dependent on heterotrimeric G-proteins, since activation of ERK2 is absent in cells lacking the Galpha4 subunit. The small G-protein rasD also activates ERK2. In cells overexpressing a mutated, constitutively active rasD, ERK2 activity is elevated prior to cAMP stimulation. Intracellular cAMP and cAMP-dependent protein kinase (PKA) are essential for adaptation of the ERK2 response. This report shows that multiple signalling pathways are involved in regulation of ERK2 activity in D.discoideum.
盘基网柄菌表达两种细胞外信号调节激酶ERK1和ERK2，它们参与生长、多细胞发育以及腺苷酸环化酶的调节。细胞外cAMP与cAMP受体1（一种G蛋白偶联的细胞表面受体）结合，可短暂刺激ERK2的磷酸化、激活及核转位。cAMP对ERK2的激活依赖于异源三聚体G蛋白，因为在缺乏Gα4亚基的细胞中不存在ERK2的激活。小G蛋白rasD也可激活ERK2。在过表达突变的、组成型激活的rasD的细胞中，ERK2活性在cAMP刺激之前就升高。细胞内cAMP和cAMP依赖性蛋白激酶（PKA）对于ERK2反应的适应性至关重要。本报告表明，多种信号通路参与了盘基网柄菌中ERK2活性的调节。
