Erg channel is critical in controlling cell volume during cell cycle in embryonic stem cells

• Published in: PloS one Vol. 8; no. 8; p. e72409
• Main Authors: Abdelhady, Shaimaa, Kitambi, Satish Srinivas, Lundin, Vanessa, Aufschnaiter, Roland, Sekyrova, Petra, Sinha, Indranil, Lundgren, Kalle T, Castelo-Branco, Goncalo, Linnarsson, Sten, Wedlich-Söldner, Roland, Teixeira, Ana, Andäng, Michael
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 02.08.2013; Public Library of Science (PLoS)
• Subjects: Actomyosin; Animals; Apoptosis; ATPases; Biochemistry; Biophysics; Blotting, Western; Cell cycle; Cell Cycle - physiology; Cell death; Cell growth; Cell Size; Channel gating; Cytology; Embryo cells; Embryonic stem cells; Embryonic Stem Cells - cytology; Embryonic Stem Cells - physiology; Ether-A-Go-Go Potassium Channels - antagonists & inhibitors; Ether-A-Go-Go Potassium Channels - genetics; Ether-A-Go-Go Potassium Channels - metabolism; Flow Cytometry; G1 phase; Gene expression; Genomes; Homeostasis; Image Processing, Computer-Assisted; Inhibition; Ion channels; Ion flux; Ion fluxes; Medicin och hälsovetenskap; Medicinsk bioteknologi; Medicinsk bioteknologi (inriktn. mot cellbiologi (inkl. stamcellsbiologi), molekylärbiologi, mikrobiologi, biokemi eller biofarmaci); Mice; Microscopy, Atomic Force; Mitosis; Molecular biology; Morphology; Na+/K+-exchanging ATPase; Osmosis; Osmotic pressure; Pharmacology; Physiology; Potassium; Protein expression; Proteins; Real-Time Polymerase Chain Reaction; Regulation; Reverse Transcriptase Polymerase Chain Reaction; RNA sequencing; RNA, Messenger - genetics; RNA, Small Interfering - genetics; Rounding; Stem cell transplantation; Stem cells; Stiffness; Time-Lapse Imaging; Sweden
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0072409

The cell cycle progression in mouse embryonic stem cells (mESCs) is controlled by ion fluxes that alter cell volume [1]. This suggests that ion fluxes might control dynamic changes in morphology over the cell cycle, such as rounding up of the cell at mitosis. However, specific channels regulating such dynamic changes and the possible interactions with actomyosin complex have not been clearly identified. Following RNAseq transcriptome analysis of cell cycle sorted mESCs, we found that expression of the K(+) ion channel Erg1 peaked in G1 cell cycle phase, which was confirmed by immunostaining. Inhibition of Erg channel activity caused loss of G1 phase cells via non-apoptotic cell death. Cells first lost the ability of membrane blebbing, a typical feature of cultured embryonic stem cells. Continued Erg inhibition further increased cell volume and the cell eventually ruptured. In addition, atomic force measurements on live cells revealed a decreased cortical stiffness after treatment, suggesting alterations in actomyosin organization. When the intracellular osmotic pressure was experimentally decreased by hypertonic solution or block of K(+) ion import via the Na, K-ATPase, cell viability was restored and cells acquired normal volume and blebbing activity. Our results suggest that Erg channels have a critical function in K(+) ion homeostasis of mESCs over the cell cycle, and that cell death following Erg inhibition is a consequence of the inability to regulate cell volume.