Potassium channel expression level is dependent on the proliferation state in the GH3 pituitary cell line

• Published in: American Journal of Physiology: Cell Physiology Vol. 284; no. 4; pp. C1054 - C1064
• Main Authors: Czarnecki, Antonny, Dufy-Barbe, Luce, Huet, Sylvie, Odessa, Marie-Francoise, Bresson-Bepoldin, Laurence
• Format: Journal Article
• Language: English
• Published: United States 01.04.2003
• Subjects: Animals; Cell Cycle; Cell Division - physiology; Cell Line; Electrophysiology; G1 Phase - physiology; Kv1.4 Potassium Channel; Pituitary Gland - cytology; Pituitary Gland - metabolism; Pituitary Gland - physiology; Potassium Channels - metabolism; Potassium Channels - physiology; Potassium Channels, Voltage-Gated; Resting Phase, Cell Cycle - physiology; Shal Potassium Channels; Time Factors
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.00446.2002

1  Laboratoire de Physiologie et Physiopathologie de la Signalisation Cellulaire, CNRS UMR 5543, Université de Bordeaux 2, 33076 Cedex Bordeaux; and 2  Laboratoire d'Immunologie et Cytométrie, Institut Bergonié, 33000 Bordeaux, France Previously, we showed that the peak density of the transient outward K + current ( I to ) expressed in GH3 cells was different in the S phase than in other phases of the cell cycle. Using cell synchronization, we show here that I to drops precisely at the quiescent (G 0 phase)/proliferating transition. This change is not due to a modification in the voltage dependence of I to , but rather to a modification in its inactivation kinetics. Molecular determination of K + channel subunits showed that I to required the expression of Kv1.4, Kv4.1, and Kv4.3. We found that the increase in I to density during the quiescent state was accompanied by an increase in Kv1.4 protein expression, whereas Kv4.3 expression remained unchanged. We further demonstrate that the link between I to expression and cell proliferation is not mediated by variations in cell excitability. These results provide new evidence for the cell cycle dependence of I to expression, which could be relevant in understanding the mechanisms leading to pituitary adenomas. Kv1.4; cell growth; excitable cell; transient outward K + current