Inhibition of EGF-induced signal transduction by microgravity is independent of EGF receptor redistribution in the plasma membrane of human A431 cells.
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.
Rijken
P J
PJ
Department of Molecular Cell Biology, University of Utrecht, The Netherlands.
de Groot
R P
RP
van Belzen
N
N
de Laat
S W
SW
Boonstra
J
J
Verkleij
A J
AJ
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
D066246:ErbB Receptors