Molecular mechanisms underlying the apoptotic effect of KCNB1 K+ channel oxidation

Xilong Wu, Berenice Hernandez-Enriquez, Michelle Banas, Robin Xu, Federico Sesti

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


Potassium (K+) channels are targets of reactive oxygen species in the aging nervous system. KCNB1 (formerly Kv2.1), a voltage-gated K + channel abundantly expressed in the cortex and hippocampus, is oxidized in the brains of aging mice and of the triple transgenic 3xTg-AD mouse model of Alzheimer's disease. KCNB1 oxidation acts to enhance apoptosis in mammalian cell lines, whereas a KCNB1 variant resistant to oxidative modification, C73A-KCNB1, is cytoprotective. Here we investigated the molecular mechanisms through which oxidized KCNB1 channels promote apoptosis. Biochemical evidence showed that oxidized KCNB1 channels, which form oligomers held together by disulfide bridges involving Cys-73, accumulated in the plasma membrane as a result of defective endocytosis. In contrast, C73A-mutant channels, which do not oligomerize, were normally internalized. KCNB1 channels localize in lipid rafts, and their internalization was dynamin 2-dependent. Accordingly, cholesterol supplementation reduced apoptosis promoted by oxidation of KCNB1. In contrast, cholesterol depletion exacerbated apoptotic death in a KCNBl-independent fashion. Inhibition of raft-associating c-Src tyrosine kinase and downstream JNK kinase by pharmacological and molecular means suppressed the pro-apoptotic effect of KCNB1 oxidation. Together, these data suggest that the accumulation of KCNB1 oligomers in the membrane disrupts planar lipid raft integrity and causes apoptosis via activating the c-Src/JNK signaling pathway.

Original languageEnglish (US)
Pages (from-to)4128-4134
Number of pages7
JournalJournal of Biological Chemistry
Issue number6
StatePublished - Feb 8 2013

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology


Dive into the research topics of 'Molecular mechanisms underlying the apoptotic effect of KCNB1 K+ channel oxidation'. Together they form a unique fingerprint.

Cite this