Growth factors modulate junctional cell-to-cell communication.
The epidermal growth factor (EGF) and the platelet-derived growth factor (PDGF) inhibit gap junctional communication in the mammalian cell lines NRK and BalbC 3T3: cell-to-cell transfer of a 400-dalton tracer molecule is reduced and junctional conductance is reduced. The inhibition of cell-to-cell transfer is reversible and dose dependent; half-maximal effects are obtained at 10(-9) and 10(-11) M concentrations of EGF and PDGF, respectively. The response of junctional conductance is detectable within 2 min of EGF application and reaches a maximum within 10 min. It is among the earliest cellular responses to this growth factor and may be significant in the regulation of growth. The response is lacking in EGF receptor-deficient NIH 3T3 cells. The transforming factor beta (TGF beta) enhances junctional communication in BalbC 3T3: cell-to-cell transfer is increased over a period of 8 hr. But in NRK cells, where it upregulates EGF receptors, TGF beta reduces junctional communication synergistically with EGF.
Maldonado
P E
PE
Department of Physiology and Biophysics, University of Miami School of Medicine, Florida 33101.
Rose
B
B
Loewenstein
W R
WR
D000818:Animals; D002450:Cell Communication; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D066246:ErbB Receptors / Q000502:physiology; D006133:Growth Substances / Q000502:physiology*; D007365:Intercellular Junctions / Q000502:physiology*; D051379:Mice; D008839:Microelectrodes; D010982:Platelet-Derived Growth Factor; D051381:Rats; D011956:Receptors, Cell Surface / Q000502:physiology; D017479:Receptors, Platelet-Derived Growth Factor; D015291:Transforming Growth Factors / Q000502:physiology
D006133:Growth Substances; D010982:Platelet-Derived Growth Factor; D011956:Receptors, Cell Surface; D015291:Transforming Growth Factors; D066246:ErbB Receptors; D017479:Receptors, Platelet-Derived Growth Factor