Apoptotic surface delivery of K channels

• Published in: Cell death and differentiation Vol. 13; no. 4; pp. 661 - 667
• Main Authors: Pal, S K, Takimoto, K, Aizenman, E, Levitan, E S
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 01.04.2006
• Subjects: Animals; Apoptosis; Biotinylation; Cell Membrane - drug effects; Cell Membrane - metabolism; Cells, Cultured; Cerebral Cortex - embryology; CHO Cells; Cricetinae; Cricetulus; Membrane Potentials; Neurons - drug effects; Neurons - metabolism; Neurons - pathology; Potassium - metabolism; Pyridines - pharmacology; Rats; Rats, Sprague-Dawley; Shab Potassium Channels - biosynthesis; Shab Potassium Channels - genetics; Shab Potassium Channels - metabolism; SNARE Proteins - metabolism; Transfection
• ISSN: 1350-9047; 1476-5403
• DOI: 10.1038/sj.cdd.4401792

Apoptosis in cortical neurons requires efflux of cytoplasmic potassium mediated by a surge in Kv2.1 channel activity. Pharmacological blockade or molecular disruption of these channels in neurons prevents apoptotic cell death, while ectopic expression of Kv2.1 channels promotes apoptosis in non-neuronal cells. Here, we use a cysteine-containing mutant of Kv2.1 and a thiol-reactive covalent inhibitor to demonstrate that the increase in K+ current during apoptosis is due to de novo insertion of functional channels into the plasma membrane. Biotinylation experiments confirmed the delivery of additional Kv2.1 protein to the cell surface following an apoptotic stimulus. Finally, expression of botulinum neurotoxins that cleave syntaxin and synaptosome-associated protein of 25 kDa (SNAP-25) blocked upregulation of surface Kv2.1 channels in cortical neurons, suggesting that target soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins support proapoptotic delivery of K+ channels. These data indicate that trafficking of Kv2.1 channels to the plasma membrane causes the apoptotic surge in K+ current.