HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by KOEGEL, H. Articles by ALZHEIMER, C. Search for Related Content PubMed PubMed Citation Articles by KOEGEL, H. Articles by ALZHEIMER, C.

Expression and biological significance of Ca²⁺-activated ion channels in human keratinocytes

Department of Physiology, University of Munich, D-80336 Munich, Germany

¹Correspondence: Department of Physiology, University of Munich, Pettenkoferstr. 12, D-80336 Munich, Germany. E-mail: c.alzheimer{at}lrz.uni-muenchen.de

In whole-cell recordings from HaCaT keratinocytes, ATP, bradykinin, and histamine caused a biphasic change of the membrane potential consisting of an initial transient depolarization, followed by a pronounced and long-lasting hyperpolarization. Flash photolysis of caged IP₃ mimicked the agonist-induced voltage response, suggesting that intracellular Ca²⁺ release and subsequent opening of Ca²⁺-activated ion channels serve as the common transduction mechanism. In contrast, cAMP- and PKC-dependent pathways were not involved in the electrophysiological effects of the extracellular signaling molecules. The depolarization was predominantly mediated by a DIDS- and niflumic acid-sensitive Cl^- current, whereas a charybdotoxin- and clotrimazole-sensitive K⁺ current underlay the prominent hyperpolarization. Consistent with the electrophysiological data, RT-PCR showed that HaCaT keratinocytes express two types of Ca²⁺-activated Cl^- channels, CaCC2 and CaCC3 (CLCA2), as well as the Ca²⁺-activated K⁺ channel hSK4. That the pronounced hSK4-mediated hyperpolarization bears significance on the growth and differentiation properties of keratinocytes is suggested by RNase protection assays showing that hSK4 mRNA expression is strongly down-regulated under conditions that allow keratinocyte differentiation. hSK4 might thus play a role in linking changes in membrane potential to the biological fate of keratinocytes.—Koegel, H., Alzheimer, C. Expression and biological significance of Ca²⁺-activated ion channels in human keratinocytes.

Key Words: ATP-evoked change of membrane potential • P2Y2 receptor and intracellular Ca²⁺ release • Ca²⁺-activated Cl^- channels • hSK4 • proliferation and differentiation of keratinocytes

This article has been cited by other articles:

				M. Raoux, C. Colomban, P. Delmas, and M. Crest The Amine-Containing Cutaneous Irritant Heptylamine Inhibits the Volume-Regulated Anion Channel and Mobilizes Intracellular Calcium in Normal Human Epidermal Keratinocytes Mol. Pharmacol., June 1, 2007; 71(6): 1685 - 1694. [Abstract] [Full Text] [PDF]

				J. LoVerme, R. Russo, G. La Rana, J. Fu, J. Farthing, G. Mattace-Raso, R. Meli, A. Hohmann, A. Calignano, and D. Piomelli Rapid Broad-Spectrum Analgesia through Activation of Peroxisome Proliferator-Activated Receptor-{alpha} J. Pharmacol. Exp. Ther., December 1, 2006; 319(3): 1051 - 1061. [Abstract] [Full Text] [PDF]

				S.-R. Jung, K. Kim, B. Hille, T. D. Nguyen, and D.-S. Koh Pattern of Ca2+ increase determines the type of secretory mechanism activated in dog pancreatic duct epithelial cells J. Physiol., October 1, 2006; 576(1): 163 - 178. [Abstract] [Full Text] [PDF]

				S. Srivastava, P. Choudhury, Z. Li, G. Liu, V. Nadkarni, K. Ko, W. A. Coetzee, and E. Y. Skolnik Phosphatidylinositol 3-Phosphate Indirectly Activates KCa3.1 via 14 Amino Acids in the Carboxy Terminus of KCa3.1 Mol. Biol. Cell, January 1, 2006; 17(1): 146 - 154. [Abstract] [Full Text] [PDF]

				S. Srivastava, Z. Li, L. Lin, G. Liu, K. Ko, W. A. Coetzee, and E. Y. Skolnik The Phosphatidylinositol 3-Phosphate Phosphatase Myotubularin- Related Protein 6 (MTMR6) Is a Negative Regulator of the Ca2+-Activated K+ Channel KCa3.1 Mol. Cell. Biol., May 1, 2005; 25(9): 3630 - 3638. [Abstract] [Full Text] [PDF]

				D.-B. Shieh, S.-R. Yang, X.-Y. Shi, Y.-N. Wu, and S.-N. Wu Properties of BKCa Channels in Oral Keratinocytes J. Dent. Res., May 1, 2005; 84(5): 468 - 473. [Abstract] [Full Text] [PDF]

				A. Zholos, B. Beck, V. Sydorenko, L. Lemonnier, P. Bordat, N. Prevarskaya, and R. Skryma Ca2+- and Volume-sensitive Chloride Currents Are Differentially Regulated by Agonists and Store-operated Ca2+ Entry J. Gen. Physiol., January 31, 2005; 125(2): 197 - 211. [Abstract] [Full Text] [PDF]

				R. Burgstahler, H. Koegel, F. Rucker, D. Tracey, P. Grafe, and C. Alzheimer Confocal ratiometric voltage imaging of cultured human keratinocytes reveals layer-specific responses to ATP Am J Physiol Cell Physiol, April 1, 2003; 284(4): C944 - C952. [Abstract] [Full Text] [PDF]

				H. Koegel, S. Kaesler, R. Burgstahler, S. Werner, and C. Alzheimer Unexpected Down-regulation of the hIK1 Ca2+-activated K+ Channel by Its Opener 1-Ethyl-2-benzimidazolinone in HaCaT Keratinocytes. INVERSE EFFECTS ON CELL GROWTH AND PROLIFERATION J. Biol. Chem., January 24, 2003; 278(5): 3323 - 3330. [Abstract] [Full Text] [PDF]

				X.D. Gong, J.C.H. Li, G.P.H. Leung, K.H. Cheung, and P.Y.D. Wong A BKCa to Kv Switch During Spermatogenesis in the Rat Seminiferous Tubules Biol Reprod, July 1, 2002; 67(1): 46 - 54. [Abstract] [Full Text] [PDF]

				M. K. Boettger, S. Till, M. X. Chen, U. Anand, W. R. Otto, C. Plumpton, D. J. Trezise, S. N. Tate, C. Bountra, K. Coward, et al. Calcium-activated potassium channel SK1- and IK1-like immunoreactivity in injured human sensory neurones and its regulation by neurotrophic factors Brain, February 1, 2002; 125(2): 252 - 263. [Abstract] [Full Text] [PDF]