title: Space flight modulates signal transduction pathway of growth factor receptors in rat osteoblasts.
abstract: Bone metabolism is regulated by the balance of bone formation and resorption. Osteoblasts serves primarily for bone formation. Microgravity deteriorates osteoblastic function and inhibit bone formation. Growth factors regulate osteoblast function via receptors. Binding of EGF and PDGF to the receptors activates receptor tyrosine kinase and rapid association of adapter proteins Shc and Grb2, and evokes the Ras/MAP kinase cascade. Signals from various chemical and physical stimuli are transmitted to the nucleus, and induce c-fos and c-jun gene expression. However, effects of microgravity on the molecular events in osteoblasts remain unknown. The purpose of this study is to investigate the mRNA levels for PDGF-beta receptor, EGF receptor, Shc, and c-fos in rat osteoblasts during space flight.
authors.affiliation: Tokyo Medical and Dental Univ.
authors.forename: Y
authors.initials: Y
authors.lastname: Kumei
authors.forename: H
authors.initials: H
authors.lastname: Akiyama
authors.forename: M
authors.initials: M
authors.lastname: Hirano
authors.forename: H
authors.initials: H
authors.lastname: Shimokawa
authors.forename: S
authors.initials: S
authors.lastname: Morita
authors.forename: C
authors.initials: C
authors.lastname: Mukai
authors.forename: S
authors.initials: S
authors.lastname: Nagaoka
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D066246:ErbB Receptors / Q000235:genetics*; D005786:Gene Expression Regulation; D016762:Genes, fos; D010006:Osteoblasts; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017479:Receptors, Platelet-Derived Growth Factor / Q000235:genetics*; D015398:Signal Transduction / Q000502:physiology; D013026:Space Flight; D014893:Weightlessness
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D066246:ErbB Receptors; D017479:Receptors, Platelet-Derived Growth Factor