Drosophila mixed lineage kinase/slipper, a missing biochemical link in Drosophila JNK signaling
Drosophila mixed lineage kinase/slipper, a missing biochemical link in Drosophila JNK signaling
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DOI：
10.1016/s0167-4889(03)00022-3
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发表时间：
2003-04-07
影响因子：
5.1
通讯作者：
Rana, A
中科院分区：
文献类型：
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作者：
Sathyanarayana, P;Barthwal, MK;Rana, A
混合谱系激酶（MLKs）属于丝裂原活化蛋白激酶（MAPKKK）家族，通过c-Jun、N-末端激酶（JNK）途径介导神经元细胞死亡。最近，在果蝇的遗传研究揭示了MLK称为拖鞋（slpr）的存在。然而，其生理底物、在不同MAPK通路中的作用以及发育和组织特异性表达模式等生化特征尚未见报道。在这里，我们报告的cDNA克隆，表达分析和生化特性的果蝇混合谱系激酶（dMLK），也被称为拖鞋。dMLK/拖鞋的蛋白质结构分析显示，除了保守的结构域，在氨基末端的谷氨酰胺和天冬酰胺-苏氨酸伸展在羧基末端的拉伸。原位杂交和逆转录聚合酶链反应（RT-PCR）分析表明，dMLK表达在早期胚胎阶段，成人脑和胸部。dMLK在果蝇S2或哺乳动物HEK 293细胞中的异位表达导致JNK、p38和细胞外信号调节激酶（ERK）途径的激活。此外，在体外激酶测定中，dMLK直接磷酸化Hep、dMKK 4以及它们的哺乳动物对应物MKK 7和SEK 1。总之，我们的结果首次提供了dMLK/拖鞋（C）2003爱思唯尔科学有限公司的全面表达谱和新的生化见解。
Mixed lineage kinases (MLKs) belong to the family of mitogen activated protein kinase kinase kinase (MAPKKK) and cause neuronal cell death mediated through c-Jun, N-terminal kinase (JNK) pathway. Recently, genetic studies in Drosophila revealed the presence of an MLK termed slipper (slpr). However, its biochemical features like physiological substrate, role in different MAPK pathways and developmental and tissue-specific expression pattern were not reported. Here, we report cDNA cloning, expression analysis and biochemical characterization of a Drosophila mixed lineage kinase (dMLK) that is also known as slipper. The protein structure analysis of dMLK/slipper revealed, in addition to the conserved domains, a stretch of glutamine in the amino terminus and an asparagine-threonine stretch at the carboxy-terminus. In situ hybridization and reverse transcriptase polymerase chain reaction (RT-PCR) analysis revealed that dMLK is expressed in early embryonic stages, adult brain and thorax. Ectopic expression of dMLK either in Drosophila S2 or in mammalian HEK293 cells leads to activation of JNK, p38 and extracellular signal regulated kinase (ERK) pathways. Further, dMLK directly phosphorylates Hep, dMKK4 and also their mammalian counterparts, MKK7 and SEK1, in an in vitro kinase assay. Taken together, our results provide for the first time a comprehensive expression profile and new biochemical insight of dMLK/slipper (C) 2003 Elsevier Science B.V. All rights reserved.