title: A requirement for K+-channel activity in growth factor-mediated extracellular signal-regulated kinase activation in human myeloblastic leukemia ML-1 cells.
abstract: Voltage-gated K+ channels have been shown to be required for proliferation of various types of cells. Much evidence indicates that K+-channel activity is required for G1 progression of the cell cycle in different cell backgrounds, suggesting that K+-channel activity is required for early-stage cell proliferation in these cells. However, little is known about the molecular mechanisms that underlie this phenomenon. We have shown in human myeloblastic leukemia ML-1 cells that K+ channels are activated by epidermal growth factor (EGF), whereas serum starvation deprivation suppressed their activity. In addition, voltage-gated K+ channels are required for G1/S-phase transition of the cell cycle. We report here that suppression of K+ channels prevented the activation of extracellular signal-regulated protein kinase 2 (ERK-2) in response to EGF and serum. However, blockade of K+ channels did not prevent ERK-2 activation induced by 12-O-tetradecanoyl-phorbol 13-acetate (TPA). Elimination of extracellular Ca2+ did not alter either ERK-2 activation or the effect of K+-channel blockade on ERK-2 activation. Our data demonstrate that the K+ channel is a part of the EGF-mediated mitogenic signal-transduction process and is required for initiation of the EGF-mediated mitogen-activated protein kinase (MAPK) pathways. Our findings may thus explain why an increase in K+-channel activity is associated with cell proliferation in many types of cells, including ML-1 cells.
authors.affiliation: Department of Physiology and Biophysics, School of Medicine, Wright State University, Dayton, OH 45435, USA.
authors.forename: D
authors.initials: D
authors.lastname: Xu
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.forename: W
authors.initials: W
authors.lastname: Dai
authors.forename: L
authors.initials: L
authors.lastname: Lu
mesh_terms: D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000502:physiology*; D002273:Carcinogens / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D016193:G1 Phase / Q000502:physiology; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000473:pathology / Q000503:physiopathology*; D019950:Mitogen-Activated Protein Kinase 1; D015221:Potassium Channels / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D002273:Carcinogens; D015221:Potassium Channels; D004815:Epidermal Growth Factor; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D013755:Tetradecanoylphorbol Acetate