This project is “Medical proteome analysis of osteoporosis- and bone mass-related proteins using the Kibo Japanese Experiment Module of International Space Station (ISS)”. Applying proteomic technologies, this research aims to identify proteins involved in spaceflight-induced deterioration of musculo-skeletal system as well as skeletal muscle atrophy and osteoporosis occurring on the ground by searching serum, bone and skeletal muscle proteomes. The goal of this study is to get better understanding to protect the health of both astronauts and osteoporosis patients. Proteome analyses of gestrocnemius muscles from male C57BL/6J mouse (microgravity and artificial 1-g [n=6, respectively]) were carried out tryptic digestion followed by LC-MS/MS analysis (DDA). The obtained results were searched against UniProt DB by Mascot, and the identified peptides were filtered at 1% FDR threshold by searching against the decoy DB. [Original project description]