Siddiqui R A, Yang Y C
Department of Medicine, Walther Oncology Center, Indiana University School of Medicine, Indianapolis 46202, USA.
Cell Signal. 1995 Mar;7(3):247-59. doi: 10.1016/0898-6568(94)00083-n.
Interleukin-11 (IL-11) stimulated [3H]phosphatidic acid (PA) formation in [3H]arachidonic acid (AA) prelabelled quiescent mouse 3T3-L1 cells. When IL-11 stimulated 3T3-L1 cells were incubated with NaF, a phosphatidic acid phosphohydrolase (PAP) inhibitor, increased PA formation was observed. In the presence of ethanol, phosphatidylethanol accumulated at the expense of PA. These results indicated that the formation of PA upon IL-11 stimulation was a result of phospholipase D (PLD) activation. Endogenous accumulation of PA by NaF treatment or exogenously added PA enhanced tyrosine phosphorylation of two proteins of 44 KDa (p44) and 47 KDa (p47) whereas tyrosine phosphorylation of other proteins was not affected. Among various PA species, dipalmitoyl PA was found to be most effective in enhancing tyrosine phosphorylation of these proteins. p44 and p47 cross reacted with anti-MAP kinase monoclonal antibody (MoAb) in both immunoprecipitation and western blot analysis. Lysates from IL-11-induced or PA-induced cells stimulated phosphorylation of a synthetic peptide substrate for MAP kinase, indicating the activation of MAP kinase in the induced cells. These studies suggest that one of the cellular signalling mechanisms of IL-11 in 3T3-L1 cells involves the activation of phospholipase D to produce the second messenger PA. The increased level of PA enhances tyrosine phosphorylation of p44 and p47 which belong to the members of MAP kinase family and thus transduces some of the mitogenic signals of IL-11 in this cell line.
白细胞介素-11（IL-11）可刺激用[3H]花生四烯酸（AA）预标记的静止小鼠3T3-L1细胞中[3H]磷脂酸（PA）的形成。当将IL-11刺激的3T3-L1细胞与磷脂酸磷酸水解酶（PAP）抑制剂氟化钠一起孵育时，可观察到PA形成增加。在乙醇存在下，磷脂酰乙醇以PA为代价而积累。这些结果表明，IL-11刺激后PA的形成是磷脂酶D（PLD）激活的结果。通过氟化钠处理内源性积累PA或外源性添加PA可增强44 kDa（p44）和47 kDa（p47）两种蛋白的酪氨酸磷酸化，而其他蛋白的酪氨酸磷酸化未受影响。在各种PA种类中，二棕榈酰PA在增强这些蛋白的酪氨酸磷酸化方面最为有效。在免疫沉淀和蛋白质印迹分析中，p44和p47均与抗丝裂原活化蛋白激酶单克隆抗体（MoAb）发生交叉反应。来自IL-11诱导或PA诱导细胞的裂解物刺激了丝裂原活化蛋白激酶合成肽底物的磷酸化，表明诱导细胞中丝裂原活化蛋白激酶被激活。这些研究表明，IL-11在3T3-L1细胞中的一种细胞信号传导机制涉及磷脂酶D的激活以产生第二信使PA。PA水平的升高增强了属于丝裂原活化蛋白激酶家族成员的p44和p47的酪氨酸磷酸化，从而在该细胞系中转导了IL-11的一些促有丝分裂信号。
