title: The effect of K(+) on caspase activity of corneal epithelial cells exposed to UVB.
abstract: Exposure of human corneal limbal epithelial (HCLE) cells to UVB triggers rapid loss of K(+) and apoptosis via activation of caspases -9, -8 and -3. It has been shown that preventing loss of intracellular K(+) can inhibit apoptosis. The goal of this study was to investigate the effect of K(+) on the UVB-induced caspase activity. HCLE cells were exposed to 150 mJ/cm(2) UVB, followed by measurement of caspase activity in cell lysates. Caspase activity was measured in the presence and absence of 100 mM K(+) in the reaction buffer. UVB-induced activity of caspases -9, -8 and -3 all decreased in the presence of 100 mM K(+). These results suggest that a role of high [K(+)] in the cell is to inhibit caspase activity. Therefore, when cells lose K(+) in response to UVB, caspases are activated and cells go into apoptosis. This supports our hypothesis that K(+) inhibits caspase activity.
authors.affiliation: Department of Biology, Calvin College, Grand Rapids, MI, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Leerar
authors.affiliation: Department of Biology, Calvin College, Grand Rapids, MI, USA.
authors.forename: Courtney D
authors.initials: CD
authors.lastname: Glupker
authors.affiliation: Department of Biology, Calvin College, Grand Rapids, MI, USA.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Schotanus
authors.affiliation: Department of Biology, Calvin College, Grand Rapids, MI, USA. Electronic address: jubels@calvin.edu.
authors.forename: John L
authors.initials: JL
authors.lastname: Ubels
mesh_terms: D017209:Apoptosis / Q000528:radiation effects*; D020169:Caspases / Q000378:metabolism*; D002478:Cells, Cultured; D019573:Epithelium, Corneal / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects; D006801:Humans; D020287:In Situ Nick-End Labeling; D007424:Intracellular Fluid / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D015221:Potassium Channels; D020169:Caspases; D011188:Potassium
keywords: Apoptosis; Caspase; Cornea; Corneal epithelium; Potassium channels; Ultraviolet