401. Microinjection of activated phosphatidylinositol-3 kinase induces process outgrowth in rat PC12 cells through the Rac-JNK signal transduction pathway
- Author
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Hiroaki Konishi, Koutarou D. Kimura, Ushio Kikkawa, Kozo Kaibuchi, Michimoto Kobayashi, Shinya Kuroda, Hideo Iba, Yoshihiro Kita, Yasuhisa Fukui, M Ui, Satoshi Nagata, and Sayoko Ihara
- Subjects
Microinjections ,Genetic Vectors ,Mitogen-activated protein kinase kinase ,PC12 Cells ,MAP2K7 ,Phosphatidylinositol 3-Kinases ,GTP-Binding Proteins ,Neurites ,Animals ,ASK1 ,Kinase activity ,MAP kinase kinase kinase ,biology ,Akt/PKB signaling pathway ,Cyclin-dependent kinase 2 ,JNK Mitogen-Activated Protein Kinases ,Cell Biology ,Molecular biology ,Cell biology ,Rats ,rac GTP-Binding Proteins ,Enzyme Activation ,COS Cells ,Calcium-Calmodulin-Dependent Protein Kinases ,biology.protein ,Cyclin-dependent kinase 9 ,Mitogen-Activated Protein Kinases ,Cell Division ,Signal Transduction - Abstract
We have previously shown that sustained phosphatidylinositol (PI)-3 kinase activity is necessary for neurite outgrowth of PC12 cells induced by nerve growth factor (NGF). Microinjection of a constitutively active mutant of PI-3 kinase induced process formation suggesting that PI-3 kinase is indeed involved in the neurite outgrowth. However, the processes appeared to be incomplete neurites as they had very poor organization of F-actin and GAP43 antigen. The microtubule network was enhanced in the process-bearing cells and process formation was inhibited by colchicine suggesting that microtubules play an important role in process formation downstream of PI-3 kinase. These cell responses were inhibited by dominant-negative mutants of Rac and Sek1/SAPK but not by a dominant-negative mutant Ras and PD98059, a MAP kinase kinase (MEK) inhibitor, suggesting that not the Ras-MAP kinase pathway but the Rac-Jun N-terminal kinase (JNK) pathway is involved in process formation.