Ion channels are linked to differentiation in keratinocytes.
In vivo and in vitro, keratinocyte differentiation is linked with increased extracellular Ca2+. In order to correlate ion channels with cell differentiation and investigate keratinocyte membrane responses to Ca2+, keratinocyte single channel currents were studied using the patch-clamp technique. The most frequently observed channel was a 14 pS nonspecific cation channel. This channel was permeable to Ca2+ and activated by physiological concentrations of Ca2+. We also found a 35 pS Cl- channel whose open probability increased with depolarization. Finally, a 70 pS K+ channel was seen only in cell-attached or nystatin-permeabilized patches. We correlated channel types with staining for involucrin, an early marker of keratinocyte differentiation. While the nonspecific cation channel and Cl- channel were seen in both involucrin positive and involucrin negative cells, all channels in which the K+ channel activity was present were involucrin positive. Membrane currents through these channels may be one pathway by which signals for keratinocyte proliferation or differentiation are sent.
Mauro
T M
TM
Department of Dermatology, School of Medicine, University of California, Davis 95616.
Isseroff
R R
RR
Lasarow
R
R
Pappone
P A
PA
D002118:Calcium / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007231:Infant, Newborn; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D015603:Keratinocytes / Q000166:cytology* / Q000378:metabolism / Q000502:physiology*; D008297:Male; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D011498:Protein Precursors / Q000494:pharmacology; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology
D015220:Calcium Channels; D002712:Chlorides; D007473:Ion Channels; D015221:Potassium Channels; D011498:Protein Precursors; D015222:Sodium Channels; C032253:involucrin; D002118:Calcium