Wu J, Spiegel S, Sturgill T W
Howard Hughes Medical Institute, Department of Medicine, University of Virginia Health Sciences Center, Charlottesville 22908, USA.
J Biol Chem. 1995 May 12;270(19):11484-8. doi: 10.1074/jbc.270.19.11484.
Addition of sphingosine 1-phosphate induces proliferation of quiescent Swiss 3T3 fibroblasts by unknown mechanisms. To identify the pathways involved, the ability of sphingosine 1-phosphate to activate mitogen-activated protein (MAP) kinase was studied. Sphingosine 1-phosphate rapidly activated the Raf/MAP kinase kinase (MKK)/MAP kinase pathway, and the concentration dependence for MAP kinase activation correlated with that for induction of DNA synthesis. Both MKK1 and MKK2 were activated by sphingosine 1-phosphate, assessed by specific immune complex kinase assays. Prior treatment of the Swiss 3T3 cells with pertussis toxin inhibited 70-80% of the sphingosine 1-phosphate-stimulated MAP kinase activity. Thus, one of the direct or indirect targets of exogenous sphingosine 1-phosphate appears to be a G(i)/G(o) protein.
添加1-磷酸鞘氨醇可通过未知机制诱导静止的瑞士3T3成纤维细胞增殖。为了确定其中涉及的信号通路，研究了1-磷酸鞘氨醇激活丝裂原活化蛋白（MAP）激酶的能力。1-磷酸鞘氨醇迅速激活Raf/丝裂原活化蛋白激酶激酶（MKK）/丝裂原活化蛋白激酶信号通路，且丝裂原活化蛋白激酶激活的浓度依赖性与DNA合成诱导的浓度依赖性相关。通过特异性免疫复合物激酶分析评估，发现MKK1和MKK2均被1-磷酸鞘氨醇激活。用百日咳毒素预先处理瑞士3T3细胞可抑制70-80%的1-磷酸鞘氨醇刺激的丝裂原活化蛋白激酶活性。因此，外源性1-磷酸鞘氨醇的直接或间接靶点之一似乎是G(i)/G(o)蛋白。
