| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2005: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2004: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
We identified a novel Rho-mDia-Src signaling pathway and a novel mDia binding protein, DIP through biochemical and cell biological approaches focusing on mDia, one of the target proteins of small molecular weight G-protein Rho. We further found that DIP inactivates Rho through p190RhoGAP activity and activates Rac through Vav2 activity both of which were Src-dependent, and that these pathways are important for spatiotemporal regulation of cell movement. Then, we investigated the involvement of the above signaling pathways found in epithelial cells in axon elongation of neurons. We observed that DIP accelerated axon elongation through the above signaling pathways downstream of mDia as we already reported that mDia has an ability to enhance the axon elongation. We also observed that mDia and DIP mRNAs are ubiquitously expressed in the mouse brain along the time course of embryo, new born and adult using both in situ hybridization and RT-PCR methods. Furthermore, we observed that DIP is localized throughout axons and dendrites from the beginning of neural extension in the primary cultures of hippocampal pyramidal neurons from new born mice by immunostaining. We ended up getting DIP-deficient mice which we began to make in 2004, and have started to analyze whether DIP is involved in neural extension in the developmental stage of central nervous system, especially in hippocampus using a immunohistochemical method. We also have started to investigate the ability of DIP to affect the neural extension in primary cultures of hippocampal neurons from both wild-type and DIP-deficient mice. We are analyzing cell movement of fibroblasts from both mouse genotypes, too. Through these analyses, we believe that we can clarify the signaling pathways involved in cell motility and cell adhesion, and that we can identify the physiological functions of DIP at an animal level.
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