title: Inhibition of EGF-induced signal transduction by microgravity is independent of EGF receptor redistribution in the plasma membrane of human A431 cells.
abstract: Epidermal growth factor (EGF)-induced c-fos and c-jun expression is strongly suppressed in microgravity. We investigate here whether this is due to inhibition of processes occurring during the initiation of EGF-induced signal transduction. For this purpose, EGF-induced receptor clustering is used as a marker. The lateral distribution of EGF receptors is directly visualized at an ultrastructural level by the label-fracture method. Quantification of the receptor distributions shows that EGF-induced receptor redistribution is similar under normal and microgravity conditions. This suggests that microgravity influences EGF-induced signal transduction downstream of EGF binding and EGF receptor redistribution, but upstream of early gene expression in human A431 cells.
authors.affiliation: Department of Molecular Cell Biology, University of Utrecht, The Netherlands.
authors.forename: P J
authors.initials: PJ
authors.lastname: Rijken
authors.forename: R P
authors.initials: RP
authors.lastname: de Groot
authors.forename: N
authors.initials: N
authors.lastname: van Belzen
authors.forename: S W
authors.initials: SW
authors.lastname: de Laat
authors.forename: J
authors.initials: J
authors.lastname: Boonstra
authors.forename: A J
authors.initials: AJ
authors.lastname: Verkleij
mesh_terms: D002462:Cell Membrane / Q000737:chemistry / Q000648:ultrastructure; D066246:ErbB Receptors / Q000032:analysis* / Q000648:ultrastructure; D005614:Freeze Fracturing; D006112:Gravitation; D006801:Humans; D007150:Immunohistochemistry; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
chemical_list: D066246:ErbB Receptors