Intracellular calcium oscillations in cell populations of ras-transfected I-7 subline of human HaCaT keratinocytes

[摘要] We have observed oscillations of intracellular Ca2+ (Ca-i) concentration in populations of rns-transfected HaCaT keratinocytes of I-7 subline. In postconfluent monolayers of I-7 keratinocytes, an increase in extracellular Ca2+ (Ca-o) concentration to 0.25-0.5 mM induced sinusoidal Ca-i oscillations, which persisted longer than 1 h with amplitudes of 50-150 nM and periods of 5-10 min, Thapsigargin, which depletes internal Ca2+ stores, did not prevent Ca-o-induced Ca-i oscillations, and it also induced Ca-i oscillations in the ras-transfected I-7 line, Removal of extracellular Ca2+ or addition of Ca2+-entry blocker La3+ or SK&F 96365 inhibited Ca-i oscillations, suggesting that Ca-i oscillations in ras-transfected HaCaT keratinocytes were dependent on Ca2+ influx across the plasma membrane, Because the Ca-o-induced Ca-i oscillations have been observed only in rns-transfected I-7 subline and not in its nontransfected parental HaCaT line, this may provide a partial explanation for the divergent responses of ras-transfected and nontransfected keratinocytes to Ca-o signal for control of growth and differentiation.

[发布日期] 1997-12-01

[关键词] Ca-i homeostasis;Ca2+ signal;cell growth and differentiation;thapsigargin