A lineage-specific Ca(2+)-activated K+ conductance in HL-60 cells.
Cells of the human promyelocytic cell line HL-60 can be controllably induced to terminally differentiate into either granulocytes or monocyte/macrophages. HL-60 promyelocytes and terminally differentiated macrophages express a K(+)-selective ion channel which is activated by intracellular free Ca2+ concentrations above 10(-7) M. Because of its voltage independence, this channel can be distinguished from the voltage- and Ca(2+)-activated family of outward-rectifying channels. The channel is selective for K+ against Na+ and is blocked by Ba2+, thus it may be similar to the Ca(2+)-activated K+ channel previously described in human macrophages. In its sensitivity to block by charybdotoxin, this channel also resembles a Ca(2+)-activated K+ channel of lymphocytes, which plays a role in activation-dependent hyperpolarization. In contrast to promyelocytes and macrophages, functional expression of the Ca(2+)-activated K+ channel is suppressed to nearly undetectable levels in granulocytes derived from HL-60 cells by retinoic acid-induced differentiation. These data suggest that signals which produce elevation of intracellular Ca2+ will hyperpolarize promyelocytes and differentiated macrophages by activating this conductance; however, signals which elevate free Ca2+ in granulocytes must act on other effectors, which may produce a different final influence on membrane potential.
Wieland
S J
SJ
Department of Anatomy, Hahnemann University, Philadelphia, Pennsylvania 19102.
Gong
Q H
QH
Chou
R H
RH
Brent
L H
LH
D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D002454:Cell Differentiation; D018999:Charybdotoxin; D006098:Granulocytes / Q000187:drug effects / Q000502:physiology; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute; D008264:Macrophages / Q000187:drug effects / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D012604:Scorpion Venoms / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014212:Tretinoin / Q000494:pharmacology
D015221:Potassium Channels; D012604:Scorpion Venoms; D018999:Charybdotoxin; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D014212:Tretinoin; D003994:Bucladesine; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium