We investigated unknown in vivo functions of Torsin by using Drosophila as a model. Downregulation of Drosophila Torsin (DTor) by DTor specific inhibitory double-stranded RNA (RNAi) induced abnormal locomotor behavior and increased susceptibility to H2O2. In addition, altered expression of DTor significantly increased the numbers of synaptic boutons. One of important biochemical consequence of DTor-RNAi expression in fly brains was up-regulation of alcohol dehydrogenase (ADH). Altered expression of ADH has also been reported in Drosophila Fragile-X mental retardation protein (DFMRP) mutant flies. Interestingly, expression of DFMRP was altered in DTor mutant flies, and DTor and DFMRP were present in the same protein complexes. In addition, DTor and DFMRP immunoreactivities were partially colocalized in several cellular organelles in larval muscles. Furthermore, there were no significant differences between synaptic morphologies of dfmrp null mutants and dfmrp mutants expressing DTor-RNAi. Taken together, our evidences suggested that DTor and DFMRP might be present in the same signaling pathway regulating synaptic plasticity. (This work was supported bythe basic science research program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (No. 2015R1D1A3A01018497)

• Phuong Nguyen(Department of Biomedical Gerontology, Graduate School of Hallym University, Ilsong Institute of Life Science, Hallym University)
• Jong Bok Seo(Korea Basic Science Institute)
• Young Ho Koh(1Department of Biomedical Gerontology, Graduate School of Hallym University, Ilsong Institute of Life Science, Hallym University)