AJP - Cell Physiology, Vol 253, Issue 4 C619-C624, Copyright © 1987 by American Physiological Society
Changes in Na+-H+ exchange regulation upon granulocytic differentiation of HL60 cells
D. Restrepo, D. J. Kozody and P. A. Knauf
Department of Biophysics, University of Rochester Medical Center, New York 14642.
The changes in activation of Na+-H+ exchange on granulocytic
differentiation of human leukemic promyelocytic HL60 cells have been
studied by measuring changes in intracellular pH with the fluorescent pH
indicator 2,7-biscarboxyethyl-5(6)-carboxyfluorescein (BCECF). It was found
that the Na+-H+ exchanger is activated by stimulation of protein kinase C
in the dimethyl sulfoxide (DMSO)-differentiated (neutrophil-like) HL60
cell, but not in the undifferentiated (promyelocyte-like) cell. In
contrast, osmotic shrinkage of the cells triggers the exchanger in the
undifferentiated cells, but not in the DMSO-differentiated cells. The data
suggest that activation of Na+-H+ exchange by osmotic shock does not occur
exclusively through stimulation of kinase C.
