Characterization of large-conductance Ca2+-dependent and -independent K+ channels in HaCaT keratinocytes.
To characterize ion channels expressed in cell membrane of human keratinocytes, patch-clamp recordings were carried out in HaCaT cells. Two types of large-conductance K(+) channels (about 250 pS) were measured. One type was activated by micromolar concentrations of intracellular Ca(2+) ions ([Ca(2+)](i)) and membrane depolarization, the other was [Ca(2+)](i) independent. The channels were neither dependent on intracellular ATP nor Mg(2+) nor on membrane stretch. We conclude that HaCaT keratinocytes express Ca(2+)-dependent maxi K(+) channels and still unknown large Ca(2+)-independent K(+) channels. These K(+) channels may affect the proliferation and differentiation of human keratinocytes by the influence on the resting potential, which may control the Ca(2+) influx across the cell membrane.
Ivanchenko
E
E
Julius-Bernstein Institute for Physiology, Martin-Luther University Halle-Wittenberg, Germany.
Markwardt
F
F
D020013:Calcium Signaling / Q000502:physiology; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects; D004594:Electrophysiology; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D051036:Large-Conductance Calcium-Activated Potassium Channels; D016014:Linear Models; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects*; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects*
D051036:Large-Conductance Calcium-Activated Potassium Channels; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated