TY - JOUR
T1 - Intercellular communication is reduced by TPA and Ki-ras p21 in quiescent, but not proliferating, NRK cells
AU - Paulson, Alicia F.
AU - Johnson, Ross G.
AU - Atkinson, Michael M.
PY - 1994/7
Y1 - 1994/7
N2 - We investigated whether the growth state of NRK cells (proliferating or quiescent by serum deprivation) affected the ability of oncogenic Ki-ras p21 and the protein kinase C activator, 12-O-tetradecanoylphorbol-13-acetate (TPA), to alter gap junctional communication. We evaluated gap junctional permeance by rate analysis of the transfer of a fluorescent dye, Lucifer Yellow, between cell pairs. We found that while the gap junctions of proliferating NRK cells were unresponsive to both TPA and to Ki-ras p21, junctional communication in quiescent cells was significantly inhibited by brief exposures to 100 ng/ml TPA. Furthermore, activity of Ki-ras p21 2 h prior to TPA exposure enhanced the inhibitory effect of TPA in quiescent cells. Junctional sensitivity to TPA was transient, with inhibition of junctional communication detected at 10 min and refractory after 60 min of continuous exposure. The suppression of junctional communication by TPA was completely prevented if the oncogenic p21 had been active for a longer period of time (48 h). The application of a phorbol ester derivative (4α-PDD), which does not activate protein kinase C, did not affect the ability of quiescent cells to communicate. From these results we conclude that there is a cell-state dependence of junctional sensitivity to TPA in NRK cells and that ras p21 activity potentiates the junctional response to TPA. One interesting possibility is that this involved a cell-cycle effect.
AB - We investigated whether the growth state of NRK cells (proliferating or quiescent by serum deprivation) affected the ability of oncogenic Ki-ras p21 and the protein kinase C activator, 12-O-tetradecanoylphorbol-13-acetate (TPA), to alter gap junctional communication. We evaluated gap junctional permeance by rate analysis of the transfer of a fluorescent dye, Lucifer Yellow, between cell pairs. We found that while the gap junctions of proliferating NRK cells were unresponsive to both TPA and to Ki-ras p21, junctional communication in quiescent cells was significantly inhibited by brief exposures to 100 ng/ml TPA. Furthermore, activity of Ki-ras p21 2 h prior to TPA exposure enhanced the inhibitory effect of TPA in quiescent cells. Junctional sensitivity to TPA was transient, with inhibition of junctional communication detected at 10 min and refractory after 60 min of continuous exposure. The suppression of junctional communication by TPA was completely prevented if the oncogenic p21 had been active for a longer period of time (48 h). The application of a phorbol ester derivative (4α-PDD), which does not activate protein kinase C, did not affect the ability of quiescent cells to communicate. From these results we conclude that there is a cell-state dependence of junctional sensitivity to TPA in NRK cells and that ras p21 activity potentiates the junctional response to TPA. One interesting possibility is that this involved a cell-cycle effect.
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U2 - 10.1006/excr.1994.1173
DO - 10.1006/excr.1994.1173
M3 - Article
C2 - 8020607
AN - SCOPUS:0028291922
SN - 0014-4827
VL - 213
SP - 64
EP - 70
JO - Experimental Cell Research
JF - Experimental Cell Research
IS - 1
ER -