Mauro T M, Isseroff R R, Lasarow R, Pappone P A
Department of Dermatology, School of Medicine, University of California, Davis 95616.
J Membr Biol. 1993 Mar;132(3):201-9. doi: 10.1007/BF00235738.
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.
在体内和体外，角质形成细胞的分化都与细胞外钙离子浓度升高有关。为了将离子通道与细胞分化相关联，并研究角质形成细胞膜对钙离子的反应，我们使用膜片钳技术研究了角质形成细胞的单通道电流。最常观察到的通道是一个14 pS的非特异性阳离子通道。该通道对钙离子通透，并被生理浓度的钙离子激活。我们还发现了一个35 pS的氯离子通道，其开放概率随去极化而增加。最后，一个70 pS的钾离子通道仅在细胞贴附或制霉菌素通透的膜片中可见。我们将通道类型与内披蛋白（角质形成细胞分化的早期标志物）的染色相关联。虽然在表达内披蛋白阳性和阴性的细胞中都能看到非特异性阳离子通道和氯离子通道，但所有存在钾离子通道活性的通道都是内披蛋白阳性。通过这些通道的膜电流可能是角质形成细胞增殖或分化信号传递的一条途径。
